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Interesting failure I had today

mpk1996

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Minuteman
Apr 25, 2013
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FL
So, I was out at the range shooting my M4. I had the range to myself, so the drills I was running were going pretty fast. After about 30-40 min of shooting after I finished one of my drills I went to put the rifle back on safe, but it would not go. I flicked it back to fire, operated fine. Same with full auto, but it wouldn't go on safe. So i dropped the mag and cleared the rifle, pulled the take down pin to have a look. nothing out of place. nothing broken that I can see. So I took it over to one of the Bravos to get a punch to start breaking it down. first we pulled the auto sear to see if that was in the way some how. Nope, sill wouldn't go to safe. so we pulled the trigger and then the safety. As we get the trigger out and roll the safety out, a spend primer, yes primer falls out. I guess running 8-10 mags in relatively fast order had heated the rifle up to the point where the brass was expanding enough to loosen the primer pocket. And on extraction and ejection the primer fell out and got wedged under the safety.

pretty interesting, as I had not see that particular failure before.

just figured I would share
 
ya, i was running m885a1, with some mk262 mod 1 mixed in.
 
that's where blown primers go. Annoying but at least nothing is broken on the gun itself.
cheers.
 
ya, i was running m885a1, with some mk262 mod 1 mixed in.

I hear M855A1 runs on the really hot side. Wouldn't surprise me if it was blowing primers. Although I'd imagine the primers should be crimped which should help.
 
It happened to me twice, back to back, on a hunt last year. I picked up my brass and they were both deprived. Popped open my receiver and one was in the trigger group and one in the barrel extension. Needless to say the load was too hot but the deer was dead.
 
Not to bash a company, but fired some Superformance rounds from Hornady in my Lr308. Way too hot for the gun. I also found the primer in the trigger mech. Don't even know if I would try that stuff in any of my bolt guns?
 
ya, the m855a1 is hotter than the reg 855. but its accuracy sucks, dispite what they say. so, if it does end of the open market, i wouldn't be in to much of a hurry to get it. plus there is a lot of over penetration on people. i wish they had stuck with the reg 855, or the 62gr barrier ammo. that stuff is accurate
 
I had a LIVE primer fall out of a reload once.... Powder all up in my shit....

It was crazy.

Posted Via Glade Plug In.

I had something similar to me but it popped out while I was seating my bullet.

After that I put all my primed unpowered cases into my 100 rd MTM box and I shake it a few times. If anything is remotely loose it'll fall out or stick out.


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I once had a bolt that stopped cycling. Nothing we did would get it to cycle. Upon dissembling the bolt, we had found a spent primer had somehow gotten into the gas key from the tiny hole in front. Unbelievable.
 
That's interesting about the Superformance.

I tried to reload a box of 223 and the primers were heavily crimped. But the flash hole burr was so severe it jacked up the brass when I used my Dillon super swager.


Sent from my iPhone using Tapatalk
 
ya, the m855a1 is hotter than the reg 855. but its accuracy sucks, dispite what they say. so, if it does end of the open market, i wouldn't be in to much of a hurry to get it. plus there is a lot of over penetration on people. i wish they had stuck with the reg 855, or the 62gr barrier ammo. that stuff is accurate

Both Mk.262 and M855A1 are too hot for high volume in the M4 or any carbine length gas system. The Mk.262 in a RLGS is pushing it, but the weapon will have more longevity since the port pressure is much lower.

Just had this conversation about SFAUC classes where somebody thought it would be a great idea to burn Mk.262 for all the CQM, and a lot of M4A1's broke bolts left and right. With M855 in one SFARTAETC course, my buddy would see a few bolts shear lugs or crack at the cam pin hole, and saw maybe 3 kabooms over an 8 year time span there.

I think M855A1 is a colossal abortion, mainly due to the pressures, followed by the nose profile and its relationship with feed ramps. It appears that someone only looked at the projectile weight and figured there should be no problem attaining M855 velocities, while totally ignoring projectile composition and bearing surface, which is as big of a deal as weight, if not bigger in some cases (like this one). Never let physics get in the way of the "me" generation though.
 
Not to bash a company, but fired some Superformance rounds from Hornady in my Lr308. Way too hot for the gun. I also found the primer in the trigger mech. Don't even know if I would try that stuff in any of my bolt guns?

The DPMS LR308's are know for short/small chambers. I wouldnt shoot anymore of that Hornady ammo in there if i was u.
 
Unless they end up in the cam slot in the bolt carrier...

Effin hate that! Had it happen to my 300, ended up having to pull the buffer tube off, and using a hammer and brass bunch to move the bolt back.... luckily no damage to bolt or upper and it still runs like a raped ape...
 
I weighed the propellant from current commercially available Fed 2013 XM855, and the charges are precisely 27.1gr of something. It shoots 'poorly' In my 24" Stag 6 Super Varminter and my 16" CMMG Bull Wasp. Like others, I believe the load, though precise, is excessive; and also attribute the inaccuracy as possibly due to bullet construction. Rifles of mine that shoot well-sub 1MOA at 100yd, are lucky to get 3"-4" at that distance with the XM855 I have. Equally bad from the Mossberg MVP Predator, and I'm not letting any of it near my Savage 11VT 'match' rifle.

Thanks for the heads-up on primers in the trigger assembly, my safety is now kinda loose and ineffectual, will look for a primer. I keep my handloads on the tamer side, so my guess goes with the XM855 being at fault here.

Question; can I tap out the safety lever without needing to reassemble anything else to reinstall it? The lower is a factory issue Stag 6.

Greg
 
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M855 is known for being mediocre at best for accuracy, especially compared to M193. The reason is they don't care too much about quality control for what was really meant to be a machine gun load for the SAW, with a steel penetrator under the nose.

That penetrator isn't exactly perfectly concentric, not is there much care about jacket concentricity and lead alloy composition.