AR .260 chews 'em up and spits 'em out...

[Predator Strikeforce]

My DPMS LR .260 has been having some issues. I need the AR experts and guru's to chime in here. Here's a list of the current issues.
1-Chewed-up and bent firing pin retaining clip. Less than 1000 rounds through the gun and this is the third retaining clip I've had to replace. Obviously somethings not right.

sideview

2-Chewed-up and broken gas rings on the bolt assembly itself. A large section is completely missing.

3-Unusual looking primers. They appear to be pierced. This occurs about 50% of the time. Sometimes they shoot out a tiny little ball of debris which gets ejected or lodged in the bolt carrier.

I can't help but think that maybe it's all firing pin related. Like possibly the firing pin is striking the primer too hard which bends the retaining clip allowing the primers to get pierced. I've repalced the pin already and nothing changed. Looks to be perfectly fine and normal too. Really, I'm totally clueless at this point. Please help and thanks...

 

[Broz]

I looks to me as if you have a different problem. But here is a thread I started years ago about a real nightmare with a 260 DPMS. As far as I know it still will not shoot some factory ammo today. But the lighter offerings where the bullet leaves the barrel faster will release the bolt to open with minimal brass smear. It to did pierce some primers too.

Sorry this pics are long gone but here is a link for what it is worth.

http://www.longrangehunting.com/forums/f23/dpms-260-issues-33955/

Jeff

 

[Bravo 4]

I haven't read the posts that Broz put in his response, so he may have helped.
But I gotta ask, have you contacted DPMS? My DPMS built .308 was having some problems. After a year of having the rifle and several hundred rounds they paid to have it shipped to them. They rebarreled it and fixed the other problem then sent it back to me with no charge.


Also, are these loads you put together yourself or factory. Big thing to consider.

 

[ICANHITHIMMAN]

Your loads are to hot! That is a youngs manufacturing BCG they are know as one of the best in regard to maching specs. However youre gas key needs to be staked they are also known for not doing that.

If dpms will not fix it send it to Steve at ADCO and have him fix the gas port size your over gassed.

 

[Predator Strikeforce]

Thanks for the advice thus far guys.

I've tried handloads and four different factory loads from four different manufacturers. That's why I never imagined that the problem could be the ammo. I'm not dismissing anyones advise at this point. I hope to find the culprit soon.

Also, the gun didn't come from DPMS directly so I can not call them. It's a semi custom build using their upper and lower. It has a Bartlien barrel, Jard adjustable trigger and Young Manufacturing bolt carrier group. The company that built the gun has been quite tough to get ahold of. Actually almost impossible.

Not familiar with Steve at ADCO. Where can I find his info?

 

[ICANHITHIMMAN]

Adco Firearms LLC AR-15, M16, M4 Carbine Gear, Parts, Accessories.

Call and talk to Marvin, tell him the issues and see what he has to say. Call between 4-6pm. 419-882-8079

Thats realy a dangerous situation you have going on and something is not right.

 

[Kevin Thomas]

I didn't see where you mentioned what powder you were using, but I suspect that this coulod also be the result of using one that is delivering too much port pressure. Switching to a somewhat faster powder might help, though ARs aren't noted for having the same degree of port pressure problems that the M1/M14 family of Service Rifles did. Just a thought.

 

[ICANHITHIMMAN]

Also forgot to add youre gas rings look fine

 

[brentc]

It might be as easy to solve as installing and tuning an adjustable gas block.

 

[WildRose]

Thanks for the advice thus far guys.

I've tried handloads and four different factory loads from four different manufacturers. That's why I never imagined that the problem could be the ammo. I'm not dismissing anyones advise at this point. I hope to find the culprit soon.

Also, the gun didn't come from DPMS directly so I can not call them. It's a semi custom build using their upper and lower. It has a Bartlien barrel, Jard adjustable trigger and Young Manufacturing bolt carrier group. The company that built the gun has been quite tough to get ahold of. Actually almost impossible.

Not familiar with Steve at ADCO. Where can I find his info?

My bet would be the throat is too short and neck too tight causing serious overpressure problems even with standard loads.

It needs to go to a good AR specialist gunsmith before it blows up in your face.

 

[WildRose]

It might be as easy to solve as installing and tuning an adjustable gas block.

That could actually cause more harm since it appears to be an overpressure problem. Restricting the flow at the gas block just adds more pressure in the chamber and bore.

 

[battlestick]

I am with WildRose....

If it were me, it would got to my smith, along with the brass for him to look at as well. I wouldn't shoot it at all until a professional looked at it.

Basic reloading says pierced primers are caused from unsafe chamber pressures. I have also seen very new BCG's (as you state yours is) get torn to pieces pre maturely from other reloaders running very hot loads all the time.

 

[stangfish]

I agree with everyone who mentioned overpresure.

Are the primers compromised on factory loads as well?

If you have a stoney point you could check to see where your lands are.

Can you post your loads including powder Bullet, weight, OAL and or BTO as well as the length to landsif you have it.