New 10" barrel, bullet stability problems

[snipecatcher]

UPDATE WITH NEW BARREL ON PAGE 8




I just got my 10" barrel in 300 BLK, and I've taken it to the range yesterday and today. It's an 8 twist with TP555's adjustable gas block, which is very well made, by the way. Day 1, I loaded up some supersonic rounds and subsonic. The subsonics were loaded with 208 A-max's and VV-N110 powder.

10 grains = 1200 fps
9.0 grains = 1100 fps
8.5 grains = 1000 fps

None of these loads were stable at 100 yards. They weren't completely key-holing, but groups were in the 5" range and the holes were oblong.

Today, I took out some new loads. These consisted of supersonics once again, and some subsonics loaded with 240 SMK's and VV-N110.

9.4 grains = 1120 fps
9.0 grains = 1080 fps
8.6 grains = 1050 fps

Once again, none of these loads were stable. Slightly oblong holes, groups in the 4" range.

I had an 18" Shilen 8 twist before this and it shot the 208's and 240's just fine, no stability problems. I'm not sure where to go from here, does anyone have any suggestions?
Regards,
-Dan

[Hoser]

Verify that is actually an 8 twist barrel. Try the cleaning rod trick.

If it isnt an 8 twist you might be stuck shooting lighter bullets.

[amafrank]

First thing is to check the crown and make sure its clean, even and centered. Any deviation can cause problems.
Next try setting targets at 50 and 150yds and see what your groups look like. That will give you some idea whether or not the bullets are settling down or getting more wobbly.
Lastly try some different bullets. Some barrels and bullets don't mix well. Change your load as well. It seems that some powders will give you identical velocity but less stability.

Good luck
Frank

[snipecatcher]

I verified that it was an 8 twist. Took it out again and shot some 155 V-max's at 900 fps. The holes were much better. Am I just crazy? I snapped a few pics of targets from the 208s and the 240s. Is it possible that they could be starting to yaw just from hitting the backerboard of the target? Maybe I just never noticed this with the last rifle.

3 shots, 208 Amax, velocity ~1000:
http://i47.photobucket.com/albums/f159/ddsr5/DSC03314.jpg


Closeup of a different shot, 208 Amax velocity unknown:
http://i47.photobucket.com/albums/f159/ddsr5/DSC03315.jpg


5 shots, 240 SMK, 1050 fps (2 in same hole, 1/2" up and to the right of target):

http://i47.photobucket.com/albums/f159/ddsr5/DSC03316.jpg

[N310toN170]

I'd move to a slower powder like IMR4227 or AA1680, see if that helps. Then after more rounds have been shot come back and try the VihtN110 again.

If it's a newer barrel and the powder is completely burning prior to the bullet reaching the muzzle it may cause erratic behavior.

[snipecatcher]

I'm sending it off to have the crown checked out, and I'm going to try to get some 1680 while the barrel is away. I'll give an update in a couple of weeks when I get it back and shooting again. Thanks for all the advice so far.
Regards,
-Dan

[Expatriot]

Those are definately unstable bullets. If you increase the range the yaw will get worse. How short an OAL are you loading? Sometimes and excessive jump to the lands can cause keyholing.

[snipecatcher]

I just got my barrel back and went out again today to check for stability. I loaded 240 SMK's over 8.5 grains VVN110. 5 rounds at 2.25", and 5 rounds at 2.17". Velocity was 1000 fps with the longer rounds, and 1040 with the shorter rounds. I still have stability issues. I threaded on an identical barrel, but in 7 twist yesterday. If I can get off work early enough and brave the weather, I'm going to test it today.
-Dan

[snipecatcher]

Braved the 33 degree temps today and took the 1 in 7 twist for a spin.

240 SMK, 8.5 VVN110, OAL: 2.25"

1022
1018
1001
1022

I loaded 5, but the gas port was still in the "Super" position for the first shot, and it didn't even hit paper. The remaining 4 made a 1.25" group, but still are not stable.

220 Sierra Pro-hunters are also not stabilizing, though I loaded them a bit light and ended up with 800 fps velocity. I'll try getting them to 1000 fps and see if it makes a difference.

I also loaded some pulled surplus 175 SMK's to ~1040 fps, and they appear to be stable.

This is driving me crazy! I'm waiting on my local dealer to pick up some AA1680, which I should have by this time next week. Until then, I guess I'll just continue to shoot supersonics in the hope that the barrel just needs to be broken in.
-Dan

[snipecatcher]

Loaded up 20 supersonic and 20 subsonic today with some 2400. It's the only powder besides VVN110 that I have that is suitable. All velocities are the average of 5 shots.

220 Sierra Pro-hunters @ 2.26"

9.5 grains: 1006 fps

10.0 grains: 1060 fps

240 Sierra Matchking @ 2.265"

9.0 grains: 1044 fps

175 Sierra Matchking @ 2.255"

9.8 grains: 1087 fps


http://i47.photobucket.com/albums/f159/ddsr5/DSC03342.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03343.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03344.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03345.jpg


I'll try the 1680 next week, but I really don't think that is going to solve the problem. I think it's something else, but don't know what. Any other suggestions? I'm thinking about single loading some 240's out to the lands to eliminate the possibility that it is the extremely long throat of the Blackout chamber. Sound reasonable?

[snipecatcher]

Results of today's shooting using VVN110 powder again:

240 Matchkings loaded long, just off the lands @ 2.29" OAL
http://i47.photobucket.com/albums/f159/ddsr5/DSC03346.jpg

155 Sierra PALMA @ 2.135" OAL:
http://i47.photobucket.com/albums/f159/ddsr5/DSC03349.jpg

Closeup showing slight offcenter hole from 155:
http://i47.photobucket.com/albums/f159/ddsr5/DSC03350.jpg


The only place to set up the chronograph this evening was in the shade, and I didn't get any readings, but I can extrapolate the data I already have and all of these loads should have been between 1000 and 1100 fps. I say "should have" because the 240's had a pretty significant thump when seated out to the lands compared to seating them at 2.26 mag lenth. Still no pressure signs on the brass. I also shot some more 220 Pro-hunters with a stiffer charge of powder that should have put them near 1100 fps. Still not hitting straight. As of today, I have 100 rounds through this barrel.
-Dan

[TCCrewchief76]

I'm wondering what kind of target backing you're using. It is possible that the noses are encountering enough resistance that it's causing the bullets to tumble before the shank exits it target. Try shooting the rounds through just the target, no backer. See if that changes things.

Kevin

[snipecatcher]

Yeah, I was thinking the same thing. Its the 3/4" thick paper type backer common at shooting ranges. Seems like I would have noticed it before with my 30/221 though. I'll make a target frame and take that to the range tomorrow. I'm also going to try shooting at 50 yards and see what it looks like. I'm willing to try about anything at this point.

[Titleiiredneck]

Yeah, I was thinking the same thing. Its the 3/4" thick paper type backer common at shooting ranges. Seems like I would have noticed it before with my 30/221 though. I'll make a target frame and take that to the range tomorrow. I'm also going to try shooting at 50 yards and see what it looks like. I'm willing to try about anything at this point.

This may have been asked before, but whats the thread pitch on the muzzle?

[snipecatcher]

It's threaded 1/2x28, the same as the Shilen barrel I had before it. The first time out, I shot it with a Noveske pig to ensure it would cycle, but I took it off after that to eliminate it as a variable. I went to the range again today and shot at 50 yards for the first time. I shot at a posterboard with no backer. Same thing. Still getting off center holes.
-Dan

[snipecatcher]

Well I've finally found a bullet that will stabilize at subsonic velocities: the 110 V-Max. I loaded some from 1400 down to 950 fps and all are making round holes. They have a calculated stability factor of 5.2 at 1000 fps. I also loaded some 175 matchkings in the 1400 fps range. These also made round holes. They have a stability factor of 4.2 at 1400 fps. It appears that I need a calculated stability factor of at least 4 in order to shoot the 300 BLK at subsonic velocities. As of right now, things aren't looking good.
-Dan

[Hoser]

Im thinking it isnt an 8 twist or maybe something along those lines...

Do you know anyone with a borescope? Might be a good idea to take a look in there and check things out.

[TCCrewchief76]

Im thinking it isnt an 8 twist or maybe something along those lines...

Do you know anyone with a borescope? Might be a good idea to take a look in there and check things out.

I was just gonna recommend that. Take a cleaning rod with a line marked down the center line. Mark the rod just as it starts to turn, and when the centerline rotates back to the top again, remark. Measure the distance between the marks, and this is your twist rate.

Kevin

[mavrick]

It might be worth a shot I have had good luck with lil gun powder in my bolt gun and my AR .

Dustin

[Titleiiredneck]

It's threaded 1/2x28, the same as the Shilen barrel I had before it. -Dan

Quick question, ya think it could be because the muzzle walls are so thin with the .308 bore vs the 1/2 od? Why I ask is had having a simmilar problem with one of my sbr uppers in 9mm. Thin walls can cause warpage when threaded, in which case it may cause the bullet to wobble when leaving the muzzle, just a thought.

[snipecatcher]

Interesting. That thought has crossed my mind too. I know 1/2x28 generally isn't recommended for a 30 caliber bore, but people still do it, and even on 9mm. The problem with that is that my 30 caliber RIFLE suppressor is threaded 1/2x28. That's just what the manufacturer uses so it can be put on a standard AR. It does bother me how thin it is, but I've been told it is fine by the suppressor manufacturer. As for the twist rate, the barrel maker measured it down to the 1/4", so I trust his word that it is a 7 twist.
-Dan

[amafrank]

Quick question, ya think it could be because the muzzle walls are so thin with the .308 bore vs the 1/2 od? Why I ask is had having a simmilar problem with one of my sbr uppers in 9mm. Thin walls can cause warpage when threaded, in which case it may cause the bullet to wobble when leaving the muzzle, just a thought.

I don't think the thread diameter and pitch are causing the issue. This thread is in use on many other .308's with no problems at all. 9MM is a larger bore and is getting much closer to the thread root so in a high pressure rifle I could see a possible issue there but not in the .308. In reality the 1/2-28 works very well in 9mm for the most part so the smaller .30 cal should have no issues whatsoever. I think there is either a problem with the barrel or the twist rate and the simplest solution is to do as others have noted and check the twist. If he's down to 110gr bullets to get a straight hole than something is seriously wrong....its not just a muzzle thread issue.


Frank

[snipecatcher]

I did try measuring the twist rate, but it is pretty tough to do when you only have about 7" of rifling to work with. I ended up with something close to 9", but I'm not sure if the measurement I got is accurate.
-Dan

[TCCrewchief76]

I did try measuring the twist rate, but it is pretty tough to do when you only have about 7" of rifling to work with. I ended up with something close to 9", but I'm not sure if the measurement I got is accurate.
-Dan

OK, I'm confused. How is there only 7" of rifling in a 10" barrel? Maybe this is your problem...:grin: Just kidding! Perhaps mark the cleaning rod on the top and bottom, and double the twist rate when you measure the rod at half-rotation.

Kevin

[snipecatcher]

Good idea. I did it that way, five times in a row, and all 5 measurements were really close. I took the average of those and ended up with about 8". Still, there has got to be something else. Even a 9 twist should stabilize a 175 Matchking at 1000 fps.

[Alleycat]

Are you shooting it with the threads bare? If you have a thread protector, shoot 3 shots with it on tight and 3 shots with it off. It's important that it's a protector and not a brake or something else that will put downward pressure on the threads. Just a little experiment.

[amafrank]

I don't think the thread protector will make any difference at all. I've fired a number of threaded rifles with no protector or suppressor and never seen any difference between doing that and having something threaded on. I've never seen any wobblies caused by having no thread protector or can either. I have seen some problems when the crown isn't square to the bore or even though.

Frank

[snipecatcher]

I don't have a thread protector. Like I said, when I got the first barrel (8 twist), I shot with a Noveske pig because I didn't know if the rifle would function. I then took it off and got the same results. I then put on the 7 twist barrel and have been using it ever since. I have not used any type of muzzle device on this barrel. I may take "the pig" with me to the range next time with the 'blast baffle' removed just to see if there is any difference. Anybody want to try the 8 twist barrel and see if you can do any better? I don't have a gas block for it, but I'd be willing to send it to one of the members on here who has a good bit of experience with this type of thing to experiment with if I can't get something to work with the 1680 powder.
-Dan

[rumlover]

did you ever borescope the barrel? Perhaps there's a burr somewhere, a warped barrel, or manufacturing mistake at the gas port. Your loads should all be working fine.

[N310toN170]

Any chance of getting a couple < 150 Grains loaded?

I usually load up a bunch of 150 FMJ BT's with cannelure and lightly crimp into the cannelure. This allows the brass to be fully fire formed at the shoulder as opposed to the soft squeeze put on by the 300/221 die when converting .223 brass. While the brass is being formed by higher pressure loads, I've seen some really strange behavior.

Once you're using fire formed brass that has been full length sized (and optimally checked for neck thickness), if your barrel won't stabilize 110-150 hypersonic then you know its a manufacturing issue that may or may not get better with use. If they do stabilize try progressively increasing bullet weight, while decreasing powder charge.

[snipecatcher]

The current barrel has 155 rounds through it, and this has all been with A) 20 pieces of FC brass formed by Hoser, or B) 15 pieces of virgin LC brass formed by me. I just recently chunked the FC brass as the primer pockets were getting inconsistent. I picked up the 1680 today and I'm going to try some loads with it either tomorrow or Thursday. If that doesn't work, I'm taking the barrel to a local machinist who is going to borescope and pin-gauge the barrel. If there is nothing wrong there, I'm going to have him cut off the threaded portion and put a target crown on one of the barrels to determine if there is something wrong with the crown/thin walled threaded portion. By the end of this week, I should know what the problem is.

As to the question about the 150's, I've put some 155 Matchkings through it and they are not stable. 110 V-max's are. I haven't tried 125's, but don't think it will matter because there is definitely something wrong here. It SHOULD be stabilizing at least the 220 round nose bullets and the 175 Matchkings without a problem. I'll keep the thread updated as I find out more.

-Dan

[TCCrewchief76]

With the problems you are having with both Subs and Supers, I'd say it's time to slug the barrel. I honestly cannot think of anything else besides an oversized barrel at this point. An oversized barrel will cause tumbling with both Subs and Supers. Slugging will also let you feel the consistency of the rifling as the slug is pushed down the bore.

Kevin

[MadDog]

I had an SSK upper that was shooting the same way. I tried multiple loads with multiple powders at various speeds. 240gr SMKs and 220gr SMKs were not stable and were all over the target. 190gr SMKs appeared stable but would not group better than about 2" at 100 yards.

I never tried any lighter bullets because I was not interested in shooting them. Never tried supersonic loads for the same reason.

I tried Corbon and SSK ammo with the same results.

The barrel was 10" long threaded 5/8 - 24 with a 3 position gas block. It was a 1 in 8 twist that I verified.

I talked to JD about it several times to no satisfaction and finally decided to send it to someone else for a new barrel. I considered sending it back to SSK and trying to make them fix it but was not confident that it would be worth the trouble and that it would be better in the end.

I really don't know what the problem was.

Good luck with your rifle. I am hoping to have my upper back soon with a new barrel.

Joe

[snipecatcher]

My last bit of hope was 1680 powder. I tried it this morning and I'm still getting understabilized bullets, of course. It's also too slow for my rifle. I had a couple cases that were covered in soot all the way to the case-head, which I attribute to them being yanked out of the chamber too early. I don't have a problem at all with this, because the faster powders that it runs best with will be quieter, if I can ever shoot the rifle with a suppressor. I'll be taking both barrels to my machinist friend on Saturday morning to try and find what's wrong with them. I've never looked through a bore-scope, and I'm looking forward to it!
-Dan

[Hoser]

Powder will make zero difference in bullet stability. Bullet speed/RPM is stabilizes a bullet.

The longer/heavier a bullet is and the slower you drive it, the faster the twist you have to have. What powder you use to get it to that magic RPM does not matter.

The borescope results should be interesting.

[i8asquirrel]

what distance are yoiu firing at?
I was having trouble with 200 nosler BT. full Keyholes at 100yds. I tried 190 gr Hornady SPBT and had wonderfull luck. ( lenght of bullet ,center of gravity?) anyway you might try some different OGive style bullets , Good luck

[snipecatcher]

I've tried a fairly exhaustive list of bullets/speeds mostly at 100 yards, a couple at 50 yards. I get the same results with both barrels. There is something wrong here. If I didn't have a bolt-action before this that ran well, I would probably be turned off by the whole idea of the 300 BLK and give up. But I KNOW that it can and does run fine when everything is right, so I'm going to stick with it. The machinist I'm going to tomorrow suggested that there may be a tight spot in the bore that is swaging the bullets down just enough to give them problems as they leave the muzzle. We shall see.

[TCCrewchief76]

What does the resistance feel like when you run a patch down the bore?

[alorton]

I'm looking forward to seeing what you find out. I've read through the thread and I'm stumped, especially since there are problems with two different barrels.

[Hoser]

I get the same results with both barrels.

By any chance were both these barrels made from the same blank?

[snipecatcher]

Different twist rates, so no. My machinist said the barrels were well made and couldn't find any faults, other than the bores were a bit bigger than expected. Usually a .300+ gauge fits very snug, and it had some wiggle room in both barrels, but he said it shouldn't have that much of an effect. The only thing he said was that he didn't see how a 10" barrel could stabilize those long bullets, regardless of the twist. People ARE shooting heavy subsonics through short barrels, correct? I know I've seen 7-10" barrels, but I've never seen targets associated with these barrels. Anyone care to post up a group shot with a short barrel and heavy subsonic loads? I'd like to see if there is any indication of them being unstable. I'm going to try some 150 grain 30/30 bullets and see if they are stable.
-Dan

[Hoser]

Different twist rates, so no. My machinist said the barrels were well made and couldn't find any faults, other than the bores were a bit bigger than expected. Usually a .300+ gauge fits very snug, and it had some wiggle room in both barrels, but he said it shouldn't have that much of an effect. The only thing he said was that he didn't see how a 10" barrel could stabilize those long bullets, regardless of the twist. People ARE shooting heavy subsonics through short barrels, correct? I know I've seen 7-10" barrels, but I've never seen targets associated with these barrels. Anyone care to post up a group shot with a short barrel and heavy subsonic loads? I'd like to see if there is any indication of them being unstable. I'm going to try some 150 grain 30/30 bullets and see if they are stable.
-Dan

I have shot lots and lots of ammo through my AR. Most of them 220 or 175 Sierras. A few 240s and some 125s. Velocities from the subs were 900-1100 fps. It is a 9.0 inch Noveske 8 twist with a Shark can.

My 300 bolt gun shoots the 220s well under MOA all day long. It is a 16.25 inch 8 twist, Lilja stainless barrel on a Remington 700 and SureFire 338 can.

No stability issues in either.

[TCCrewchief76]

Once spin is established, it shouldn't matter how short the barrel is. Again, it's time to slug the bore and see where things are for sure. I'm a bit surprised that the bore is as sloppy as it is on the lands. That's gonna have an effect on how much grip the bullet sees. Try and recover a projectile and see what kind of impression the rifling is leaving.

Kevin

[Mike Bell]

I just read a precision handloading book that it doesnt matter the length of the barrel or fps....the twist is the twist. If you go faster or slower, its still the same revs per distance.

[rsilvers]

fps matters as that is what makes the rpm go up or down.

As for barrel length, it does not matter for gyroscopic stability but there are other forces acting on the bullet - such as the muzzle blast. Very short barrels don't seem to be as accurate as normal barrels.

[alorton]

My barrel is a 10.5" Noveske and it shoots 208gr Amax's and 240 SMK's fine. I think the AAC Blackout barrels are going to be 16" or 9" and I've not heard of any of those having problems with stabilizing bullets. Short barrels have been used for years with 300 Whisper in the T/C pistols as well.

The length shouldn't be the problem.

[Mike Bell]

Sorry if Im a little slow...but this stuff is realitivly new to me because it never mattered before (to me) now that I have built a 300 wtf ever we call it....Im trying to learn everything around this stuff. So...

RPM's increase because FPS increses, but the twist rate is the same. So if he has to maintian around 1000pfs for subsonics loads....he would then have to increase the twist rate. But his twist is within the proper rate.

Was this barrel chamber recut to the 300 BLK from a whisper or 30/221 chamber before? Im wondering if the longer throat is forcing the bullet out-of-wack? OR.......

And Im wondering if it was not a regular 30 caliber barrel? maybe a .302 or .303 barrel?


After re-reading to entire thread twice.....two different barrels are making me think that its not the gun...but the relaoding set up. Have you tried ammo made by someone else??

This sucks for you Snipecatcher, but I think some of us are learning alot.

[snipecatcher]

I shot some 160 Hornady FTX bullets today. They are the 30/30 bullets with a rubber nose, and are fairly short. I only tried 2 charge weights, and ended up around 1200 fps. They were stable at 50 yards. I also loaded up some 90 grain XTP pistol bullets. They are the only bullet I've tried that will not feed. I was single loading them. They were all stable. The lightest load had them around 1000 fps, and 16 grains of VVN110 had them going 2000 fps. The supersonic load went through one gallon jug of water and stopped in the second. Retained weight 58 grains, expansion to over 1/2".

As far as my loading process goes, I really don't think that's it. I've been using the same Redding dies that I used for my 30/221 bolt action. Only one load I shot through the bolt action wasn't stable, and it was a 155 pushed by Red-dot to around 600 fps. Those hit the target completely sideways. Other than that, I never had a problem stabilizing any load in that barrel.

[snipecatcher]

Also, I'm sending my 1 in 8 twist barrel off to Hoser sometime this week. He is our resident ammo expert, so maybe he can come up with something that works. I'd really just like to get this figured out for the good of all. Also, it's driving me insane.
-Dan

[fasttwist]

I have a .308 winchester in a 10twist that wont stabalize anything subsonic. When I recovered a bullet I noticed I have what apears to be a high land in the barrel. On the other side of the bullet the baring surface is smeared = shitty chamber job. This maybe forcing the bullet into the rifling at a strange angle. I would try to catch a subsonic projectile. I would also try a bullet of a larger caliber-.310-.311.

[snipecatcher]

Thanks for the advice, and I wish I would have thought of that yesterday. I drove 2 hours to a place on private property where I can shoot however I want. I was shooting into a mound of sand. I didn't even think to try and find one of the 240's, which was stupid, as I doubt they could have gone far going sideways. I may try to work something out with a guy I know down here to fire a bullet into a mound of sand and dig it out. I'm leery of shooting a 310 bullet out of a 308 bore, especially with this cartridge. I know people do it with the 7.62x39, but the risk of going over-pressure, or sticking a bullet is too high for me.
-Dan

[snipecatcher]

I slugged the bore, but I'm not sure what it's telling me. From land to land, it's .306. From groove to groove, it's .308. This seems normal to me. Everything looks uniform all the way around. I'm ordering some 150 grain round nose Sierra Pro-hunters to try. I think these are the heaviest bullets I'll be able to use in this rifle.
-Dan

[pud-knocker]

I slugged the bore, but I'm not sure what it's telling me. From land to land, it's .306. From groove to groove, it's .308. This seems normal to me. Everything looks uniform all the way around. I'm ordering some 150 grain round nose Sierra Pro-hunters to try. I think these are the heaviest bullets I'll be able to use in this rifle.
-Dan



.306/.308 ????

sounds like a pistol barrel land/groove ratio, a shot-out pistol barrel.

.299 to .300/.308 is what I would think you would want in a .308 rifle barrel.

[snipecatcher]

That's the best I can come up with.

Looking back at all of my data:

175's need to be going 1500 fps to be stable.
110's are stable down to 950 or so.

Plugging these numbers into JBM's stability calculator, I theoretically have about a 10 twist barrel. This is figuring in at least a 2.2 stability factor, which I've read is necessary when shooting subsonic.

[Titleiiredneck]

If you would like to catch your bullets you can shoot into 6" of wet media "phonebooks are best I have found" Try a 200+ grain projectile should work fine, if it penetrates you may need 2 more books "I live in a small area so I needed 4 to start with" I have used this method on subsonic 45 9mm 357m and 45lc in the past and it worked well. You will want to use a bthp as the plactic tip types may deform too much.

To test get a 5gal bucket of water, soak books and place them in a milk carton or wood frame. Books need to soak for about 5 minutes or less otherwise the glue may unbind. If you cant get phonebooks you can always go by wallyworld and buy a few packs of printer paper, that should work as well.

[TCCrewchief76]

.306/.308 ????

sounds like a pistol barrel land/groove ratio, a shot-out pistol barrel.

.299 to .300/.308 is what I would think you would want in a .308 rifle barrel.

That sounds like Marlin Microgrooving to me. Those lands should be measuring around .300", plus or minus a thou. That bullet is just being slid down the barrel with wreckless abandon. I'm surprised that thing even hits paper being a "smoothbore" and all...
If you think about it, those lands are only .001" high. Time to get a barrel replaced.

Kevin

[fasttwist]

Well, at least you found your problem. I would like to see the jacket of the bullet that came out of that barrel.

[BWE Firearms]

Who is the barrel manufacturer? If your measurements are correct your barrel is way out of spec for a .308 dia. barrel. I want to make sure I never use that brand of barrel in any of my work.

[snipecatcher]

Going to get a couple bags of sand and headed out to the range. I'll catch a few bullets and see what they look like. Barrel is a Douglas.

[snipecatcher]

Bullets were going into the sand and then turning sideways, so half of the bullet is "sanded" rough, impossible to see rifling. It's tough to get any data out of the 4 bullets I recovered. I called Douglas Barrels today and they said to send it in. I'll ship it out today, so no new info for at least a couple weeks when I hear back from them, unless Hoser gets a chance to mess around with the barrel I sent him.
-Dan

[snipecatcher]

It's tough to tell what's going on unless you can look at them up close and run your fingernail over the grooves, but I've tried to point out what's going on:

This picture is showing what appears to be one very wide land where the bullet didn't catch the rifling. The width of the line is where one ridge starts, spanning to the other side.
http://i47.photobucket.com/albums/f159/ddsr5/Recovered240SMK.jpg

The top arrow points to where it looks like the bullet first hit the rifling in the throat, and the bottom arrow looks like where the bullet left the barrel.
http://i47.photobucket.com/albums/f159/ddsr5/Recovered240SMKII.jpg


I suppose this explains why my barrel was behaving like a 10 twist. The bullets weren't getting the full effect of the twist, as they were skipping the rifling. I think we have figured it out. I hope Douglas agrees and takes care of me on this. I am very thankful to all who have helped me along this frustrating endeavor.
Regards,
-Dan

[i8asquirrel]

Glad to hear you figured it out!

[snipecatcher]

I know everyone has seen a fired bullet, but I thought I'd throw this one in for a head to head comparison:

208 A-max recovered from 30/221 Shilen barrel. Note nice clean rifling:
http://i47.photobucket.com/albums/f159/ddsr5/DSC03369.jpg


Also thought you might enjoy this one. Hornady 90 XTP (.3085 diameter) 2000 fps. I blew up the first jug, soaking my rifle, my chronograph, and myself, and stopped in the second jug, blowing out the side of the jug. Mushroomed quite nicely. This would be an excellent bullet if you want limited penetration:
http://i47.photobucket.com/albums/f159/ddsr5/DSC03362.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03364.jpg

[TCCrewchief76]

That's awesome Snipe! Does that round feed from the magazine? What load are you using with that bullet?

Kevin

[BWE Firearms]

I have been using Douglas barrels for 30 years and am surprised something like that got out. Let us know what they do to correct this.

[snipecatcher]

That's awesome Snipe! Does that round feed from the magazine? What load are you using with that bullet?

Kevin

They are the only bullet I've used thus far that will not feed from the magazine. 16 grains of VVN110 gets it to 2000 fps in a 10" barrel. OAL is only 1.65". This would be a pretty neat load if it would cycle reliably. Someone should make a handgun for it. :grin:

[TCCrewchief76]

That's what I was thinking!

Kevin

[snipecatcher]

Just got off the phone with Stan at Douglas Barrels. Good people. He said they don't make many of the fast twist barrels in chromoly, 99% of people order them in stainless. Because of this, their button for the chromoly rifled barrels hasn't got much attention, and was out of spec. They need to make a new button, which will take a couple weeks, so he offered to replace my barrels with stainless. He will be sending Paladin a new stainless blank, 1 in 7 twist. I can't wait!
Regards,
-Dan

[rsilvers]

Maybe they don't have a chrome-moly button in that twist and used 1:10 twist bullon but spun it at 1:8 or 1:7.

[snipecatcher]

I don't think so. He was pretty upfront about everything. He just said I was the first person to have an issue, probably because I'm one of the few people who didn't go stainless. Either way, I'm not blaming anyone for this. Stuff happens; it's how the company deals with it after the fact that matters. Both Douglas Barrels and Paladin Machine (TP555) have been as helpful as they can in taking care of this, and I really appreciate it.
Regards,
-Dan

[rsilvers]

Stainless makes sense for one-off barrels. If we did not do nitriding, we would be doing stainless - for the bolt guns at least.

[sha-ul]

Stainless makes sense for one-off barrels. If we did not do nitriding, we would be doing stainless - for the bolt guns at least.

that whole nitriding process sounds very interesting... ans I've heard you can do stainless as well

[rsilvers]

You can do 416 stainless, but the result is much less corrosion resistant than if you do carbon steel.

This is why S&W was getting rust when they Melonited their M&P stainless slides. Glock uses carbon steel and - never rust. So nitriding stainless is not only more expensive, but a worse result.

The ultimate barrel is carbon steel with nitride.

[snipecatcher]

While we are on the subject: CAN a nitrided barrel be machined, or is there some type of preparation to remove the nitriding before machine work? As an example, say I wanted to have a different muzzle thread on a nitrided barrel. What's the process?
-Dan

[rsilvers]

You can machine it with carbide tooling.

We have taken our 9 inch nitrided barrels and chopped some to 7 inches.

[Mike Bell]

Robert,

I work at MGW Precision in Augusta GA. We make parts for other companies besides our self, and some of them have stop having me blue their parts becuase they went to the Melonite finish. Where can I find more info about this process?

We are an O.E.M. supplier but we have our own line of gunsmithing tools and some pistols parts (1911) that we might try out.

My boss is into cars so he is really doesnt care much for the gun stuff......We tried like heck to get him into the AR rifle market and you know what he said....."AR's are just a fad....it wont last." little does he know!!!!

[HotLead]

Mike,

check out the H.E.F. site; here is a link:

http://www.hefusa.net/melonite-QPQ-arcor.htm

Here is the link to the Accurate Shooter site that has the H.E.F. pricing and point to contact info:

http://www.accurateshooter.net/Adverts/meloniteorderform.pdf

Now that I have my can, I plan to have this done to my TP555 300BLK barrel.

[snipecatcher]

Got the new stainless barrel from Douglas. Other than being stainless, the specs are the same, it's a 10" with 1 in 7 twist. The results are looking better, but I'm still not sure. I have some targets from today:

http://i47.photobucket.com/albums/f159/ddsr5/DSC03433.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03435.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03436.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03437.jpg

http://i47.photobucket.com/albums/f159/ddsr5/DSC03438.jpg


The 240's appear to be ok at 10 yards, but the holes still aren't perfect. I don't feel comfortable shooting them through a suppressor. At 100 yards, they are not stable either. Some make round holes, some oblong. They are marginally stable. If I up the charge and get them going 100 fps faster (into supersonic territory) they get better.

The 208's make nice round holes at 10 yards and at 100. They are also fairly accurate.

The 220 Pro-hunters shot the best group of the day at 1.15", but appear to be unstable. This is strange considering they are quite a bit shorter than the 208's.

[Retooferab]

What powders are you using? I have had good luck with N110, AA9, and 1680. My most developed loads are 8.6gns N110 and 8.2gns AA9 I have been using 2.09 oal keep in mind that for about every .10 oal you can change about a .1 gn..... ........I have been using 220SMK bullets


What I am saying is if your load is 8.7gns using say 2.19 oal if you change the oal to 2.09 you should reduce your load .1gn to keep the same velocity.
At least this is how it is working in my 10.5" ar.

[snipecatcher]

I've used 3 different powders, at many charge weights, trying many combinations of bullet/seating depth. So far, the only bullet that appears to work in this barrel is the 208 Amax. I took some with me this weekend and shot them at 150 yards, and they were stable, BUT, my load was a consistent 1120 fps. I mis-judged the charge weight a bit. I'm going to load up some more at 1050 fps and see how they shoot. It sucks being stuck with one bullet, which is perpetually out of stock, but if they work, I'll make the 200 or so that I have last.
-Dan

[buffetdestroyer]

I've used 3 different powders, at many charge weights, trying many combinations of bullet/seating depth. So far, the only bullet that appears to work in this barrel is the 208 Amax. I took some with me this weekend and shot them at 150 yards, and they were stable, BUT, my load was a consistent 1120 fps. I mis-judged the charge weight a bit. I'm going to load up some more at 1050 fps and see how they shoot. It sucks being stuck with one bullet, which is perpetually out of stock, but if they work, I'll make the 200 or so that I have last.
-Dan

Snipecatcher,that really sucks that you are still having stability issues, but maybe 175, 180, 190 or 200 gr. might work if you are just barely stabilizing the 220+ grain bullets. It should have the same effect of tumbling at that point but won't have as much overall energy if you are using them for hunting.

You might also try fire lapping the barrel and see if it is just something from in the rifling that needs to be polished out. Shoot me a PM if you need some lapping compound for making DIY fire lapping bullets and I can let you borrow mine.


I have yet to see 208 Amax's in stock since I have been loading my .300 WTF so I don't know if I can believe that they really exist yet! :tongue:

[snipecatcher]

Even 168 SMK's were not 100% stable. I know what you mean about the 208's! I bought 500 of them for $20/100 when Midway had its' last big Blem bullets sale. Thanks for the offer on the lapping compound. I'm going to keep playing with it, and if I can't get anything else to work, I may take you up on that.
Regards,
-Dan

[Retooferab]

What powders are you using and what velocities are you loading to?

[snipecatcher]

I've documented a lot of it in this thread, but I'm using AA1680, VVN110, and Alliant 2400, and I've tried everything from 900-1200 fps. I've tried lots of combinations/charge weights/etc., burned through probably $100-200 worth of components, and I arrive at the same result. I'm going to keep experimenting though. In fact, as I'm typing this, my Chargemaster is metering out 2400 for supersonic loads. The supersonics are great. I killed a pig with them on Saturday. This may end up being a supersonic only rifle.

[Retooferab]

You will get it worked out. These guns are simple and there is something that is just a little off. I am going to read through the thread again. I am no expert but I am pretty good at figuring things out or I might know the right person to ask.

[snipecatcher]

150 Nosler Ballistic tips are the worst yet. They are unstable at 1300 fps, and from 1050-1200 fps, they are hitting the target at about a 45* angle. Shot some more of the 208's today at 100 yards, and got a 10 shot group that measured 2.5", with only about an inch of vertical dispersion. This was shot at a blank sheet of paper, so the horizontal dispersion could have either been my aiming ability or the 10-15 mph wind.

So far, all of the 208 A-max loads appear stable, but this one is the winner:
OAL: 2.265"
8.8 grains VVN-110
Velocity:
High: 1052
Low: 998
Average: 1020
SD: 14.79

[snipecatcher]

Update:

Had a baffle strike in my suppressor, and the only thing I had been shooting that day was 110 V-max's supersonic, and 90 XTP's subsonic. The 90 XTP is the shortest/lightest bullet you can load. The can was on tight the whole time, I check it often. SOMETHING kicked out and knocked a baffle out of place. I have concluded that my barrel does not stabilize ANY bullet at subsonic velocity to a degree that is safe to shoot through a suppressor. When I get my can back, I'll just stick to supersonic loads. Aaron at Delta Company Arms heard about my situation and has agreed to cut me a deal on one of his 300 BLK barrels in the next few months when he has some in stock.
-Dan