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Post by GLSHOOTER on Oct 23, 2015 9:32:50 GMT -8
So, ran a function test with a magazine full of 130 grain Barnes over 28 grains of RL7 after opening up the gas port and doing the bolt work. I'm getting consistent ejection....reliable ejection, but still "weak". It's throwing at the 2 o'clock position and only about 2 feet.
My thoughts, after reading Glenn's result, is headspace. maybe the shoulder needs to be bumped up a bit more than it is now so the ejector can fully grab the case rim. My barrel is an 18" mid, as well, threaded, but NO muzzle device, just thread protector. My gas block is a Yankee Hill Low Pro, btw.
This sounds strange to me because I know, by simple seating force, the case rim SHOULD fully seat when chambered.
Thoughts? The shoulder location in this instance has zero influence on your extraction/ejection. A change in powder and powder charge would probably give you totally different response. A standard gas block may actually choke the gas flow in some instances. I prefer a bigger port with adjustments to tune each load. My goal is to get the case out of the gun. The minutia of under/over is not something that overly concerns me unless they dramatically affect function and brass abuse. Sometimes a stronger extractor spring combined with stronger ejector springs will make a huge difference. I know I NEVER run the little O rings in the extractor and when I get one I take it out. I think the increase in tension is just too much. Greg
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Post by geepee3 on Oct 23, 2015 15:19:52 GMT -8
So, ran a function test with a magazine full of 130 grain Barnes over 28 grains of RL7 after opening up the gas port and doing the bolt work. I'm getting consistent ejection....reliable ejection, but still "weak". It's throwing at the 2 o'clock position and only about 2 feet.
My thoughts, after reading Glenn's result, is headspace. maybe the shoulder needs to be bumped up a bit more than it is now so the ejector can fully grab the case rim. My barrel is an 18" mid, as well, threaded, but NO muzzle device, just thread protector. My gas block is a Yankee Hill Low Pro, btw.
This sounds strange to me because I know, by simple seating force, the case rim SHOULD fully seat when chambered.
Thoughts? I'm in agreement with Greg. Headspace should not be an issue with the problem your having. Even when I use light loads to fire form new brass for the first time. I get proper ejection and the bolt carrier locking after the last round. That's with a BTE adjustable gas lock. And I even have it restricted. You should seriously consider trying a BTE adjustable micro gas block. I have them on both my 18" BHW barrels. Glenn
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Post by cpct on Oct 23, 2015 18:18:22 GMT -8
I've done all the mods Greg and Glenn have suggested, except the gas block. I'll order one soon. I can live with what it's doing now, but why not make it 100% reliable? BTW...it does hold bolt open on the last round.
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Post by cpct on Oct 23, 2015 18:22:17 GMT -8
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Post by cpct on Oct 23, 2015 19:05:51 GMT -8
Or this one?
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Post by GLSHOOTER on Oct 23, 2015 19:17:04 GMT -8
I use a lot of those. Greg
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Post by geepee3 on Oct 23, 2015 20:19:27 GMT -8
That's the style I use. The one with the set screws. BHW has the dimple on the barrel to help line it up and keep the gas block in place. Glenn
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Post by cpct on Oct 24, 2015 7:47:42 GMT -8
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Post by cpct on Nov 9, 2015 20:11:50 GMT -8
Installed the gas block, got it adjusted, and shot this....100 yards..8 shots. Still trying to figure out why some primers are very flat, and some are normal with the same powder charge. Oh well..new challenge.
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Post by GLSHOOTER on Nov 10, 2015 5:44:31 GMT -8
Installed the gas block, got it adjusted, and shot this....100 yards..8 shots. Still trying to figure out why some primers are very flat, and some are normal with the same powder charge. Oh well..new challenge.
Did you run a chronograph? That might show you some indication of variation in the primers. Also if the shoulders are different height, i happens, you may see variations in primer appearance as the case has more room to move before coming against the bolt face and it tends to flatten. Greg
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Post by cpct on Nov 13, 2015 5:54:42 GMT -8
Those are my exact thoughts, Greg. I took another measurement of the fireformed brass from the above group. I was loading those at 2.095 using the "9mm Method" Ritch told me to use. I reset the sizing die for 2.104....006 back from formed. I was pushing the shoulder back too far.....015 instead of Ritch's recommendation of only .006. This should take care of things, once and for all. My loaded overall length is 2.295 on those Barnes 130's. I haven't chronographed them. I'll do that on the next batch to be fired and let you know. I'm guessing low 26's. I was also adjusting the new gas block. Maybe that had something to do with pressures? Anyway, this thing is going to be a great hog killer. This California drought has taken them to the coast range. Pretty scarce in the Central Valley. I cancelled that hunt from earlier this year....
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Post by cpct on Nov 13, 2015 6:00:32 GMT -8
Here's an interesting thought.....I'm using RCBS dies. Do you think there's any difference between those and the Hornady dies you guys are using? I wouldn't think so since the Herrett has been SAAMI speced.
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Post by GLSHOOTER on Nov 13, 2015 6:16:41 GMT -8
The dies are OK. They won't make any discernible difference. The shoulder set back is a huge issue and as you adjust the gas block you will find some changes in the primer appearance. The over-gassed loads will look flatter than the under-gassed, Also the case head damage decreases as you lower the opening speed somewhat.
Greg
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Post by cpct on Nov 13, 2015 19:29:45 GMT -8
We're definitely on the right page. Thanks. I just loaded another 36 for fire forming tomorrow. The dies are set where they should be now, so I'm done....I think...hehehe. With accuracy like the above target, There's going to be A LOT fewer hogs this winter in Central California...
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