DPMS AR15

[jboot]

A hangfire (or a squib-I'm not sure which you are describing) may be an ammo problem, but the jam sounds like a gas system issue. When an AR doesn't cycle it means that there is insufficient gas pressure against the bolt carrier. I'd check:

1. The bolt carrier key (described in my last post).
2. The gas tube itself. A quick-and dirty way to do this is to hold a finger over the muzzle and blow canned air down the gas tube. If you can feel air coming out of the chamber, it is probably OK.
3. The ammo. Squibs and hangfires aren't all that common in modern ammo. I've never seen one in an AR and all I've ever shot is junk ammo (Wolf and Brown Bear). If an inappropriate powder was used the ammo itself could be producing insufficient gas or too much combustion debris. Try some other ammo.

Failing all that, it COULD be a manufacturing problem. I've seen or heard of gas blocks not aligned with the gas vent on the barrel, burred gas vents, crushed gas tubes and "custom gas systems" dialed all the way shut right out of the box.

[MaxMax]

My DPMS had the Bolt taken out of it and replaced with a cheap aftermarket before purchase.
The store made it right and have had no problems since, you should check the bolt manufacturer.
If there is no stamp you should be concerned.

[TalonDJ]

I had it happen in a family member's .380. In that case, I didn't realize there was still a round in the barrel.

I had that happen to a 380 once as well. Fortunately I noticed and stopped firing. It was the only time that has happened to me.

[Joe Brower]

AR-15 Q&A thread.

Figuring out these sorts of problems is akin to tuning a car over the phone. I don't know what FReeper hdbc's level of knowledge is on this subject; it might be advisable to use this thread for some ideas, but take it to a reputable gunsmith to hash out. There are too many possible causes for this to decipher without hands and eyes on. I've seen rifles behave like this (except for the stuck bullet in the barrel) from a simple lack of lubrication.

That said, I've run a couple thousand rounds of several brands/types of .223 and 5.56 through an A-15 M-4gery (non chrome-lined barrel) without a hiccup. No steel-case stuff, though.

[TheThirdRuffian]

Wanna buy another?

[DCBryan1]

Buy a shrike upper and be done with it ;)

[Bloody Sam Roberts]

Try an extra power spring for the extractor

That's how I resolved my extraction problems. A heavier spring from Wolff.

[from occupied ga]

Take the bolt out of the bolt carrier and make sure all three gas rings have their gaps evenly spaced at 120 degrees to each other.

[Tenacious 1]

Even a gas tube completely off the rifle wouldn’t account for a bullet not having enough gumption to get clear of the barrel completly.

It was a government bullet. They are all no-good-lazy-bottom feeders. It wasn't even trying.

[Tenacious 1]

Before the mishap on the Chesapeake last year or so, I had my DPMS AR-15 since 2008.

I recall some FReepers used to make fun or get sideways about that old running "lost em in a boating accident" issue. Not so funny today though, huh?

I bet some of those "That's a dumb thing to post" nay-sayers are suddenly recalling their prized collection of guns and ammo being lost at sea these days too.

;o)

[Georgia Girl 2]

Likely the extractor claw spring is not strong enough to contact the rim and get a clean ejection every time. I would get an after market stronger extractor spring. Windham makes one and so does I think Colt.

On that particular weapon I would also probably go to a titanium firing pin as this speeds up the strike time. Actually you may need a whole new bolt carrier so you may just want to take it back to the dealer and make them fix it.

Or you might just want to turn that one back in and if you can get a refund trade up to Windham or a Colt or Daniel Defense. But the Dealer will probably just want to try to fix it.

[MHGinTN]

When a barrel nut is not 'torqued to proper tight' even one round can cause the barrel nut to rotate pinching the gas tube. The proper fix is to take the barrel off of the upper receiver and reinstall with a new barrel nut and torque it properly with the gas tube unpinched right through to the bolt carrier.

I had a guy bring me an AR which he wanted to mount a piston kit to because his rounds were not cycling right. Turned out his gas tube was pinched by a loose barrel nut. If the barrell had roatated further (if the tube was not holding it from rotating off) he could have blown it up in his face!. I used a brand new barrel nut to reattach the barrel when mounting the piston kit.

[MHGinTN]

See my #52 on this thread.

[lacrew]

A general comment on this thread.

Lots of speculation about nuts not being tight enough, gas tubes not being aligned, bolts not being staked, headspace, etc....

I have never seen a problem like that. Admittedly my experience was with the M-16; but, I assume the operating principles are very similar. We abused the heck out of our M-16’s...and to be blunt, every armorer I ever had was not too bright - they were made the armorer because nobody trusted them on their tank, etc. So, lets just say they didn’t do alot of spring adjustment and bolt staking (I was the ‘arms room officer’, so I am a firsthand witness).

Yet, somehow the rifles always worked. The only problem we would have would be with blanks, or if somebody accidentally did something very destructive to the rifle.

If its a squib that happened to you, I think that’s very dangerous, as far as presures are concerned. I’d take it back to the seller, or if that isn’t an option, have a gunsmith look at it. Something is dangerously wrong with the thing.

[MHGinTN]

I build, tune, and work on Ars alot, and I would bet the problem is a barrel nut that was not torqued down.

[CodeToad]

If a bullet gets stuck in the barrel it is not the rifle. It is the ammo.

[Buffalo Head]

There is a general misperception among the shooting public and Law Enforcement personnel that the .223 Rem and 5.56mm Military cartridges are identical – just a different designation used for commercial and military purposes– and can safely be interchanged. The fact is however that although somewhat similar, they are not identical and dangerous high pressures and safety hazards can result from firing some types of 5.56mm ammunition in .223 Rem chambered firearms.

• The cartridge shellcases of each have essentially the same length and exterior dimensions. • Mil Spec 5.56mm ammo typically has higher velocities and chamber pressures than the .223 Rem. In fact, the chamber pressure of each is tested by entirely different methods in different chamber configurations. The resulting data cannot be meaningfully interchanged or interpreted by applying a simple correction factor. • The 5.56mm cartridge shellcase may have a thicker sidewall and a thicker head than the commercial counterpart - to better withstand the stresses generated by the higher chamber pressures. This situation, however, reduces the powder capacity of the military shellcases - which can create higher than safe pressures if reloaded using load data and components intended for commercial .223 Rem cartridges. . • The 5.56mm and 223 Rem chambers are also similar but are not identical. The primary difference is in the "Throat”. The throat is defined as the cylindrical portion of a chamber between the shellcase mouth shoulder and the conical “Leade” portion that tapers down to the bore dimension. The throat in a. 223 Rem chamber usually extends only .085” in front of the shellcase mouth position. In a 5.56mm chamber the throat is typically .162”, or almost twice as long as in the 223 Rem chamber. • One can safely fire commercial 223 Rem. cartridges in military 5.56mm chambers with this longer throat, but will usually experience a slight loss in accuracy and velocity – compared to firing the 223 round in the chamber with the shorter throat for which it was designed. • Functional and safety problems may occur when firing the higher pressure 5.56mm cartridge in a 223 Rem chamber with its much shorter throat. It is generally known that shortening the throat can dramatically increase chamber pressure. In some instances, this higher pressure can result in primer pocket gas leaks, blown cartridge case heads, and poor gun functioning, each of which can be personal safety issues. • The 5.56mm military cartridge fired in a 223 Rem. chamber is considered by SAAMI (Sporting Arms and Ammunition Manufacturers Institute) to be an unsafe ammunition combination and is listed in the “Unsafe Arms and Ammunition Combinations” Section of the SAAMI Technical Correspondent’s Handbook. It clearly states; “In firearms chambered for 223 Rem – do not use 5.56 Military cartridges.” • Federal’s XM193 packaging currently has a warning that states “For use in standard 5.56 Chambers. Do not use in non-standard 5.56 chambers.” This warning is also listed on the XM193 Product Specification Sheet. Winchester Ammunition has a similar warning on their USA brand 5.56 ammunition packaging: “Use only in firearms in good condition designed and chambered by firearm manufacturer specifically for this 5.56 ammunition and so marked on the firearm.” • Some commercially available AR15’s, M4’s and M16’s – may in actuality have been manufactured with 5.56 mm chambers although stamped .223 Rem on the receiver. it is the user's responsibility to know for which cartridge their firearm was chambered and choose their ammo accordingly. If you have any questions about chambering, check directly with the firearm manufacturer.

[Dead Corpse]

I have four. My next one will be a .308. Possibly a DPMS LR-308.

Thanks though. ;-)

[Dead Corpse]

Glad I wasn’t drinking coffee or that would have killed another keyboard... ;-)

[Dead Corpse]

Its not a garden hose. If it was “pinched”, some moron was wrenching on it to get it “pinched”.