AR10 308 problems
What up y'all? Your boy Nemesisenforcer here. Been awhile since I rapped at ya. What have i missed?
Anyway, here's my issues: got 2 AR10s in 308. One is a diamondback brand the other is a polymer 80% lower I built with a Stoner upper. I'm having extraction/ejection problems in both of them. Stovepipe, extractor ripping through rims, short stroke on bolt closing, incomplete extraction, etc. I'm using my standard handload 150 grain spritzer with 3.1cc (42-43 grains) of IMR4895 powder.
Thoughts?
Anyway, here's my issues: got 2 AR10s in 308. One is a diamondback brand the other is a polymer 80% lower I built with a Stoner upper. I'm having extraction/ejection problems in both of them. Stovepipe, extractor ripping through rims, short stroke on bolt closing, incomplete extraction, etc. I'm using my standard handload 150 grain spritzer with 3.1cc (42-43 grains) of IMR4895 powder.
Thoughts?
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First thing would be to test fire them, with different military and commercial ammo. To see if the problem(s), are with your loads, or with the rifles. The type and amount of powder used, can be very problematical with semi-autos.
If the problem(s) are universal with all types of military and commercial ammo? A adjustable gas bloc might be required. To tune the rifle(s) to a specific load.
I don't mean to criticize. But using a polymer lower for a high recoil impulse cartridge like the .308 is questionable, IMHO. I use to work in the aerospace industry. Where polymer, was the required euphemism. Because they didn't want the sheeple to know, they were flying on a mostly plastic airplane. It boggles the imagination, but most folks don't know polymer and plastic. Are the same. Polymer just being the weasel word for plastic.0 -
I was also thinking it is a gassing issue.......as far as polymer lowers in the AR design family of rifles.....if I am correct, polymer lowers work in these rifles because all they do is house the trigger group and controls.....all of the forces of recoil are confined to the upper receiver and bolt carrier group/buffer assembly.rufe-snow said:If the problem(s) are universal with all types of military and commercial ammo? A adjustable gas bloc might be required. To tune the rifle(s) to a specific load.
I don't mean to criticize. But using a polymer lower for a high recoil impulse cartridge like the .308 is questionable, IMHO. I use to work in the aerospace industry. Where polymer, was the required euphemism. Because they didn't want the sheeple to know, they were flying on a mostly plastic airplane. It boggles the imagination, but most folks don't know polymer and plastic. Are the same. Polymer just being the weasel word for plastic.
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My understanding, is that where the buffer tube screws into the back of the receiver. Is the achilles heel, for the plastic receivers. This is apparently where the failures occure. Because of this, the high quality plastic receivers are reinforced in this specific area.mohawk600 said:
I was also thinking it is a gassing issue.......as far as polymer lowers in the AR design family of rifles.....if I am correct, polymer lowers work in these rifles because all they do is house the trigger group and controls.....all of the forces of recoil are confined to the upper receiver and bolt carrier group/buffer assembly.0 -
Thanks rufe-snow 0 -
What you've missed? Thanks to Trump I got government funding for my MATEN build (AR10) so I too got an AR10 up. I also learned when the butt is bumped hard enough it'll self load a shell.
Stove pipe I'd say gas system, buffer and spring. Rifle length gas tube? Do you have an adjustable gas block? Have you looked to see how rough the chamber is to see if they're extra grippy? Or the BCG is trying to grip and rip the still expanding shell. When I do go to the range I'm expecting to leave the jacked up shells there.
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Armalite recommends 168 grain pills for their AR-10's. Got any factory loads with that weight? 0 -
All good suggestions. Thanks guys. I'll look into a few things and report back. 0 -
Since both rifles are having the same or similar problems, yet are different by construction, I suggest that you try some 'standard' .308 Win. Match loads first to establish a performance line for comparison. These Match loads will necessarily be using 168 gr. Match bullets which are the standard for the .308 Win. rifles. You will need a chronograph, of course.
Your 'standard' load may be a standard to you and your uses but it is not the industry standard. Test for the industry standard then we can adjust whatever might be taking place with your loads. Start at the beginning then move forward. This eliminates a bunch of guessing.Best.3 -
" extractor ripping through rims, short stroke on bolt closing, incomplete extraction,"
On an AR15 platform, I'd call this an over gassed condition or ammo too hot. AR 10's may have some different dynamics but similar operating systems should display similar symptoms.
extractor ripping through rims: often resulting from bolt trying to open before residual chamber pressure has dropped enough to allow the brass to "release" from the chamber walls
incomplete extraction: basically same causes as ripped rims only at a slightly lower level
short stroke on bolt closing: not sure what this means but my perception is the bolt is cycling too fast and over running the next round in the magazine
All of these may be the result of over pressure ammo or over gassing. ASSuming the correct combination of buffer, tube, and spring are in place, the first and easiest suggestion: get some plain vanilla .308 factory ammo and see if the symptoms continue.3 -
Where exactly can I find factory ammo in this environment?Mobuck said:" extractor ripping through rims, short stroke on bolt closing, incomplete extraction,"
On an AR15 platform, I'd call this an over gassed condition or ammo too hot. AR 10's may have some different dynamics but similar operating systems should display similar symptoms.
extractor ripping through rims: often resulting from bolt trying to open before residual chamber pressure has dropped enough to allow the brass to "release" from the chamber walls
incomplete extraction: basically same causes as ripped rims only at a slightly lower level
short stroke on bolt closing: not sure what this means but my perception is the bolt is cycling too fast and over running the next round in the magazine
All of these may be the result of over pressure ammo or over gassing. ASSuming the correct combination of buffer, tube, and spring are in place, the first and easiest suggestion: get some plain vanilla .308 factory ammo and see if the symptoms continue.0 -
I just received an email ad from Classic Firearms with numerous brands and types of .308 ammo IN STOCK and acceptable prices, too. 3
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