Charges and Seating Depth

[JFettig]

I've been doing some research and some loading. I now have about 100 rounds through my 10.5" pistol.

I loaded 20 220 SMKs with 9.2gr of H110, a load I borrowed from spook, I did this only after verifying it with many other loads. I put 5 through a chronograph and they started at 940-50 and got up to 1070fps just in those 5 rounds, not very consistent. Some had flat primers and some weren't as flat. All of these were loaded to 2.220" I read that loads with H110 should not be reduced more than 3% rather than the normal 10% reduction, does this have to do with empty space and can it be fixed by changing seating depth? What is the best way to determine seating depth?

I have mainly shot 147gr Win FMJBT with 15 and 16gr of H110(started at 15), the 16gr H110 loads were mostly consistent at 1750-1780fps, I did get a few that I didn't put through the chronograph that the primers didn't flatten out as much as the rest. All of these are seated to 2.150".

From the ones that didn't flatten the primers much, the shoulders weren't blown out as much as the ones that had flat primers. I had no case head expansion on any of these cases.(formed LC 5.56 brass)

I plan to load some 165gr soft points, 125gr sp or hp, and determine what I want to shoot primarily. I don't have a can so I don't plan on shooting much for 220s, They do however have the most energy at long ranges when loaded supersonic.

What about loading light bullets subsonic, like 168 gr boat tails? The subsonic 220s I loaded were nice, light, and very quiet compared to the 147s.

Is there a more ideal powder than H110?


Thanks,
Jon

[pug]

With a pistol you may be able to cycle 168gr loads you will have to try it and see. The gas port has to be larger the lighter the bullet you use but you may be fine. Since you have H110 on hand you can try 8.5gr with the 168s for subsonic and see.

[JFettig]

Any thoughts on seating depth and charge sizes for consistent shooting?

Jon

[pug]

My notes say 2.200" for 168gr SMK with 8.5gr of H110 but that is all. Not whether it is starting load or most accurate.

[JFettig]

Thanks for the info pug, I'm more looking for that info on the 147 supersonics and primarily the 220 subs .

Shot 10 125gr TNTs at 2000fps, 2.100" OAL. All went off flawlessly.

Jon

[dksd39]

for my 220's I have 2 subsonic loads that are in the 1020-1050 range:
8.7gr LiL Gun
11.6gr RL7- this is a compressed load

as for seating- I have not played with it much

[pug]

If you are using H110 still go to www.quarterbore.com and look under subsonic and supersonic. I think I used those loads when I was trying H110.

[steezo757]

After this weekend, I've decided to to use H4227. I loaded up 10 rounds with 10 grains behind 220gr SMKs. Used the first 5 to check for function (cycling and bolt holding open) and sighting in (so my chronograph doesn't get damaged).

Here's what the last 5 did:

1096
1081
1102
1087
1090

The accuracy was excellent.

I loaded up the next batch at 9.9grs to hopefully bring the velocity closer to 1050 - 1075. My Lee powder measure likes the texture of H4227. The finer powders will leak out of undesired areas.


BTW, here's my setup.

AR with a 10.5" barrel and .100" gas port in the pistol position

[JFettig]

Pug, I did check out the loads there but OAL isn't listed.

Am I corect when I assume that air space in these rounds with H110 should be kept to a minimum? This is what I am assuming when I see that charges should be kepth within 3% of the specified load and that I am seeing lots of deviation in my rounds which I carefully measured out all of the charges but maybe seated too long?

Steezo, thanks, I'll look into that powder.

Is Lil Gun the ideal powder to use? I've read a lot about that powder around here lately.

When I get back to the shop in 2 weeks, I'll open my gas port up a little and possibly make an adjustable gas block.

Thanks,
Jon

[pug]

I would try some more loads before opening the port up. Perhaps someone has some AA#9 you can try. That worked well with subsonics also.

[JFettig]

I measured my port and it is .083" according to my calipers, I think tp555 driled it to .08 if I remember correctly.

I'll look into AA#9. Not sure if I know anyone who has any. Until I buy or find some, I'll stick with supersonic loads and take your advice against opening it up. The plan was to open it to .090 max.

Thanks,
Jon

[pug]

Each gun is different but I would think you should be able to cycle subsonic loads down to 180gr bullet weight with that. You had mentioned shooting a lot of 147gr bullets and I am pretty sure it will not cycle those subsonic unless you open it up. Opening it up will allow you to cycle the lighter bullets but on the other hand you shave more bullet and will require adjustable gas to shoot supersonic.

[320pf]

I measured my port and it is .083" according to my calipers, I think tp555 driled it to .08 if I remember correctly.

I'll look into AA#9. Not sure if I know anyone who has any. Until I buy or find some, I'll stick with supersonic loads and take your advice against opening it up. The plan was to open it to .090 max.

Thanks,
Jon

I have all on my 300-221 fireball barrels drilled out to 0.083. The gas ports in my rifles is in the pistol position and I can reliably shoot 165 gr bullets sub-sonic.

Pug is right on about the suggestion to use AA#9. That is the powder I use. I have also have some success with Alliant 2400.

You now have my curiosity peaked. I wonder if I can get my rifles to shoot 150-155 grain bullets in the sub-sonic realm? I think that I will give it a try this weekend.

320pf

[pug]

My notes from early on indicate that I was using H110 with the 150s. That was before I drilled out the port I am pretty sure. They list 150gr set to cannelure with 8gr H110 would cycle but not lock back. 8.2gr would cycle but not lock back. 8.5gr would cycle and lock but went supersonic after barrel warmed up. The only notes on #9 I kept seem to be for the 255gr hollow points. 8.9gr of #9 would push the 255gr HP at 1033 fps. Doesn't do you much good but thought I would throw it in there.

[JFettig]

I took some friends to the range to shoot up some of my ammo and I brought the whisper along to put a few more rounds through it... forgot the subs though.

I put about 10 rounds through it, 4 of them failed to eject, some failed to extract... I had my .223 AR with so I decided to pull the bolt carrier out of that and put it in this just for the hell of it and sure enough, it ran perfectly. I then tried to put the BC I had in the .300 in the .223, released the bolt and it would not go into battery all the way! It was hell to get it out! I think I found the culprit, I'll be sending that bolt carrier back to DPMS as soon as I get it back to my dealer.

If all goes well this week, I'll load up some more subs and see if I can get them to cycle.

Jon

[Ron458]

Jon, could you measure the bolt lugs? I wonder if they are longer & hitting the brl & extension inside. Need to keep an eye on the DPMS bolts! Ron

[JFettig]

Jon, could you measure the bolt lugs? I wonder if they are longer & hitting the brl & extension inside. Need to keep an eye on the DPMS bolts! Ron

Just measured the lugs out, .739 diameter on the bolt that works and .741-.742 on the bolt that doesn't. The other dims were all the same.(length of the lugs, depth of bolt face, etc.)

Both will chamber the dummy rounds just fine and they extract smoothly in my .300, I dropped in the one dummy I had made up in .223 and it closed real tight, I have a dirty chamber I see now, I'll clean that up tonight and see if I can figure something out. The chamber in the .300 is clean, not sure what the deal is. I'll take it out with the other carrier next time I go out and see if I can get any stoppages out of it.

Jon

[Ron458]

The extension has room for the .742 so it should be fine. Another idea would be to switch carriers to be sure it is the bolt. Let us know what you find out. Ron

[JFettig]

I picked up some #9,
What do you think of these charges from Acurate?
http://www.accuratearms.com/data/PerCaliber2Guide/Handgun/Standarddata/30Cal(7.62mm)/300%20Whisper%20page%2076.pdf

I only have 220s right now, I figured I'd load a few in that area to chrono for next time I go out to the range.

Jon

[pug]

Loads look good to start with. As far as the bolt if you have a dial caliper run the step end down into the cup of the bolt face and measure the depth. See if the one giving trouble is equal or not as deep as the other.

[JFettig]

That dim I did check, both .125" right on the money. Looks like saturday's plans cleared up, I should be able to take this to the range and do some testing. I have some 165gr bullets so I'll try to load some subs with those too. I'll see if I can figure out what the deal is with these bolts.

Jon

[JFettig]

Well, I made it to the range.
Regarding the BCG, from swapping carrier assemblies I found that my hard chrome carrier assy was still the only one having issues, I swapped bolts and the HC bolt still has issues.

I tested a couple loads,
18gr H110, 125gr TNT 1950-2000fps.
7.4gr AA#9, 165gr SP 950,1030fps, only shot 2, very abnormal primers.
8.1gr AA#9, 220gr SMK, ~1020fps, didn't cycle but ejected.

The 165gr subs acted very strangely! The primers actually pushed out a bit on both, one flatened more than the other, the other was very rounded, around the firing pin and such, sounded like a .22. One ejected, the other jammed in the ejection port.

Any recomendations?

Jon

[Pitt300]

I've had great results w/Rem PSPs w/8.3g H110 & 16" barrel w/762SD.
Avg Vel 1066fps.
Cycled fine in semi auto operation.
See attached:
http://www.quarterbore.net/forums/photopost/showphoto.php?photo=383&cat=562

[Pitt300]

This is the "cheap" load that I use if I'm letting someone shoot my 300-221 for silenced effect @ paper.
I added 13" of elevation to my "normal" scope setting for supersonics.
Bought 500 of these from Midway & am almost out & need to find more @ a decent price.
Who else sells Rem bullets by the 500 pak?

[JFettig]

Whats your OAL on that load?

Wideners has a decent deal on 168gr match bullets.

Jon

[Pitt300]

Should be on Target
2.138"

[amafrank]

Jon,
Your likely problem with the primers doing funky stuff in the subs is due to low pressure. Normally the primers will push out of the pocket to take up any room left by headspace. When pressure reaches its peak the case is forced back to the bolt face and reseats the primer. If the pressure is on the low end the case may not come back far enough to seat the primer again. Sometimes they reseat but the primers look odd like they have been flattened to one side and they look like hot load primer flow. I have some loads I know are light and yet the primers say they are hot by the look. Sounds like you are at the same place here....failure to clear the ejection port sounds light load like..... The only fix if you feel its a problem is to change powder. Not sure whether to say go slower or faster but you need to get the pressure peak to move to a different point in the cycling.

Just my opinion of course.

Frank