Model 1 Sales 300 whisper upper function problems

[mac66]

sharpshooter33,
The barrel was turned and chambered by Mike Orwan. The upper/lower and bolt carrier are Bushmaster. It has a standard length buttstock/spring. Shortly after I recieved mine Mr. Orwan began to place the gas port in the pistol position with better success from a wider range of sub/supersonic loads (per his website). I did initially try a standard gas tube with resultant failures to extract/eject. The rifle was basically a single-shot. Loads consisted of 125-190 grain bullets at close to maximum powder charges (supersonic loads) from Quarterbore or Accurate reloading data. I formed the cartridge form G.I. 5.56 brass. The only thing that really helped was a liberal coating of gun oil to the bolt carrier. This did improve performance somewhat. I will try a chrome carrier that I have to see if this makes a difference by friction reduction. All parts are almost new. Maybe the system need further "breaking in".
Last night I opened up the gas port to .125 and will try to put the rifle back together this week for a testfire early next. I'll review the powders that I loaded with to make sure they are on the slower end or the burn rate scale in effort to get the pressure to peak near the gas port. I put the Pigtail on hoping to lengthen the time the pressure was acting on the bolt carrier. I think the 5.56 round is rated at or around 60,000 CUP. The closest pressures in a subsonic round that I have seen is Accurate #2 that is no longer recommended for .300 subsonic loads. I thought the Pigtail might make up for the difference. We will see.
Anyways, thanks for the input. I'll get back to the board after I test fire next week. It sound like we all have about the same rifle configuration. Hopefully, we can find some common avenues to increase weapon reliability with sub/supersonic loads. Thanks again.

[jripper]

I'll summarize what I figure out during my trials with the model 1 upper:

Make sure you bolt works freely. Mine was very stiff, and once it broke in, it worked a lot better.

Opening up the gas port to .120 or larger.

Also, for sub sonics, slower powders work better: I found AA 1680 would cycle even with slow (850fps) loads, but W296 would not. I found either to work well with supersonics (125 grain and 168 grain).

I hope this helps.

Joel

[sharpshooter33]

Originally Posted by jripper

Update:

I think I have this thing figured out. It will run reliably with 220 and 240 graind Sierra's, subonic. Put 20 rounds of 11 gr. AA 1680 and 220 Sierra bullet through last Sunday, and ejection was quite positive. Did not chronograph, but they were very quiet, and almost had to be subsonics. I did chrono the 240s with 10.3 g AA1680, and they were only going 850 fps (they did run, however).

jripper,
What primer are you using? I was looking at my Sierra book for pistol loads for the 300Whisper and it looks like there using Federal 250M which I think is a magnum pistol primer???? and they are using 11.7gr AA1680 in a Contender 10" to get 1000fps. Have you had a chance to Chrono the 11.0gr 220gr SMK load yet? I just worked up some 220gr SMK with 11.0gr AA1680 and CCI 400 SR primers. Let you guys know how they do on Friday. Don't have access to a Chrono so I won't be able to report on that.

SS33

[jripper]

No, I have not chronograph that load. I will probably do that this week. I believe I was using federal small rifle primers (standard, not magnum).
It burns every bit of powder, and I don't think a magnum primer is going to make much difference.

Right now, I have been going by sound and feel, and it would appear to be subsonic, but I'll Chrono to check.

I don't know about the rest of you, but I am seeing a lot of variation from listed loads, vs. what I am getting from my own gun.

I have also seen a lot of variance on what different people are calling a maximum load.

For instance, I am using 18.5 grains W296 behind a 125 rem. psp. Some people list a max load of over 21 grains. Past 18.5, I am blowing primers out of the cases!!!

I guess that it what can happen when working with a semi-wildcat.

Joel

[sharpshooter33]

Ok I've been tinkering with my 300/221 for awhile now. I have a load that duplicates the Corbon 220 Subsonics on paper, but does function my action. I'm using 11.0 gr of AA-1680. With my setup cases/primer/seat depth etc... I'm getting the same sight settings on the Corbon 220subsonics as I am with my 220gr subsonic reloads. The difference is mine cycle the action.

My AR cycled fine with lockouts on my last round. My problem and question is....That it failed to extract on several cases. I've examined the extractor and it looks fine. Unknown if the spring is strong enough or not though. The second possibility could be that the action is trying to pull the casing out before the pressure has went down (or the bullet has left the barrel)

Has anyone else experienced this problem?

I'm shooting a 300/221 M1S 16" barrel, CAR length AGT full open and with full size stock and buffer setup. Is there any signs that I can look for to indicate which it may be?

I'm going to replace the extractor spring 1st then if that doesn't work I'm going to be clueless.

I did notice that I could hear the bullet impact at 100yards and also on the recoil I could see the bullet right before it struck the target at 100yrds. That was funny. I was using the Corbons and single feeding them. I even let a friend watch it through the scope on a couple of rounds. It didn't leave oblong holes. The bullet was stabalizing. I don't have a Chrono, but I would say they are in the 850-1000fps range.

Anybody have any input I would appreciate some thoughts on this one

[rednek58]

I know two things that might help you with the failure to extract. D-Fender brand ring that fits around the extractor spring, also a heavy Wolff extractor should help. Either one alone might work, but I have used them together with good results. Hope this helps.

[sharpshooter33]

Ok, I've fixed my extractor problem. I now have a fully functional 300/221 fireball from Model 1! I'm using Jrippers load of AA1680 at 11.0gr and 220gr SMK's sized alittle longer than Corbon's, but they still fall below 2.260 OCL. I've used RP and LC cases and both are just fine. This load seems to be shooting somewhere around 950fps.

I'm a happy camper! Now I just have to get a suppressor and my project will be complete.

BTW when I put it back together I ordered a MRFS-C and drilled a hole for my AGT. It is a bad ass looking setup right now. Will be even nicer when I get it suppressed.

I see a 300/221 bolt gun in the future also. I'd like a real quiet one. 8-)

Thanks for all the input here guys. I would never known I had a problem unless I was reading these posts and I wouldn't have known how to fix it either.

Thanks
SS33

[jripper]

Glad to here your upper is running well. Mine is also, altough a few weeks ago, a friend came over, and we went to try it out, and I got failure to feed/extract short stroking again, sub sonic or super sonic. When I pulled ou t my bolt, I found that the carrier key had come loose. I then noticed that the "staking" on the model 1 bolt did not even touch the allen screws. I put red loc tite on them, and staked them a little deeper, and it all works again.

Just something to check if you are using a model 1.

Thanks everyone here for their help, as I don't think I could have gotten it going without the input here

Joel

[jripper]

I finally chronographed my 11.0 AA 1680 and 220 sierra load. Out of my 16" M1S ar, 3 shots averages 980, with a high of 1020 and a low of 933.

Only did three, as that was all I had on hand, and it was starting to rain.

Joel

[dlt223]

Hello All,
I chose to go with a PacNor Barrel Blank, finished by John Noveske.
He recommended a Port Diameter of .125" since that is the ID of the Gas Tube.
He also recommended the port at the Pistol position.
I chose to stay with the carbine position, since I am using the JP adjustable Gas Block.
This setup works well and I am able to tune for various Loads.
E-Ya Later, Dave