Dpms is scaring me a little.

[Pointman308]

So I was out it with my son yesterday helping him sight his new 3G2 on paper. The gun shoots great for a gas gun, but as it cycles the next round into the chamber it leaves small firing pin dents into the advancing round. It scares me that one might go off before it goes into battery. Can any one chime in on this?

 

[Layton]

That's normal for an AR. Floating firing pin makes contact with the primer when the bolt slams shut leaving that small indent. It's ok just don't cycle the same round over and over. Having said that I've cycled the same round 3-4 times and never had one pop off. I've just heard the gap between the cap and anvil can close enough to cause a slam fire.

L

 

[Pointman308]

That's kind of what I was thinking, but was still a little concerned thanks.

 

[George Az]

That is the way we could tell if a young trooper chambered a live round.....happens in Colt A/R's as well. It is why some folks do not use certain primers when reloading, if the primer is known as a sensitive primer. I do congratulate you on your observation skills if you weren't taught to look for it. You are paying attention.

 

[Pointman308]

Thank you sir.

 

[Layton]

I use BR4s in mine and never had an issue but I rarely cycle a round more than once. I may just try to get one to go off at the range next time to see how many cycles it takes.

 

[leadbullet]

Every AR15 does it, nothing to worry about unless you are using federal primers, BR primers are a waste of money in gas gun too.
Cheers.

 

[Pointman308]

I wouldn't do that, because it may go off before it's in battery and explode. That's just my thought on it.

 

[Layton]

When the bolt travels forward the firing pin is actually in the rearward position due to the acceleration of the bolt. Only when the bolt slams shut does the firing pin travel forward under it's own velocity to make contact with the primer. There's no danger as long as I have control of the weapon and it's pointed in safe direction.

 

[elfster1234]

This why i use cci 41 primers in my 556 ar's. Ill still use 400's but im slowly switching over to 41's when possible. I think if youre having an excessive amount of this id keep an eye on it. Might be part of the break in process and might go away with use. Another reason to keep the fire pin and bolt clean after each use IMO

 

[Layton]

This won't go away and cleaning will just let the firing pin move more freely thus impacting the primer faster/harder. It's perfectly normal on this platform. BR4s are pretty soft and I've yet to have a slamfire with around 1600 fired on this lot I have. If your AR isn't doing this you may need to clean it.

edt: I use a single feed block so there is no resistance on the bolt to slow it down a little stripping the round out of the mag.

 

[Tacsnipe73]

It is physically impossible for your g2 to fire out of battery, as the firing pin cannot contact the primer until the bolt is fully closed and locked.
What can happen is that after prolonged and repeated bolt closures on the same round, it can ignite the primer without the trigger being pulled....

 

[E. Bryant]

What can happen is that after prolonged and repeated bolt closures on the same round, it can ignite the primer without the trigger being pulled....

... or, you can damage the primer to the point where it won't go bang when you really want it to. This is of non-trivial concern in duty or self-defense firearms.

 

[Pointman308]

I've learned a lot thanks gents.

 

[ZombieMonkey]

As E. Bryant stated, the more common failure I've seen here has been excessive chamberings in the AR causing the primer to not ignite once you actually want it to go bang. Yes, slam fires can happen with the floating firing pin can happen, they just are not as common from what I've seen with guys chambering the same round at the PD.

When I would chamber a round I just made a habit of throwing it into the range pile after replenishing it with a new one if I had to chamber a round because I was deploying the AR for a call. Removes the possibility.

 

[pinsandpitons]

Is anyone here aware of a confirmed slamfire due to a floating firing pin in an AR-15 style weapon? I'm not talking, "it's theoretically possible under such and such circumstances", or "uncle ben heard of a guy whose rifle blew up when xxx" but hard fact that a slamfire was caused by a floating firing pin in the absence of a faulty trigger group, or other malfunction. I recognize the theoretical mechanism of such a malfunction given the design, but am extremely skeptical, (emphasis on extreme) that it is anything but a theory. I'm no armorer with millions of rounds under my belt on hundreds of different examples so I'm really asking.

 

[Hollywood 6mm]

I've spent a fair amount of time shooting ARs, and have friends that have round counts in the millions through issued weapons. I have never seen, nor heard of a slam fire from rechambering the same round over and over.

I HAVE heard of (and seen - once), a round fail to ignite due to the primer bring crushed from repeated chamberings.

 

[samnev]

Most 308 Ar's the M1A and the Garand do the same thing to primers so beware.

 

[Scottmilk9]

Is anyone here aware of a confirmed slamfire due to a floating firing pin in an AR-15 style weapon? I'm not talking, "it's theoretically possible under such and such circumstances", or "uncle ben heard of a guy whose rifle blew up when xxx" but hard fact that a slamfire was caused by a floating firing pin in the absence of a faulty trigger group, or other malfunction. I recognize the theoretical mechanism of such a malfunction given the design, but am extremely skeptical, (emphasis on extreme) that it is anything but a theory. I'm no armorer with millions of rounds under my belt on hundreds of different examples so I'm really asking.

I have a lot of rounds down range through AR's and am an armorer and never seen a slamfire caused by the floating firing pin. The only slam fires I have seen is trigger/sear failure. I have built custom AR's for 15 years, plus 11 years military, so you're safe.

 

[*Nine]

Is anyone here aware of a confirmed slamfire due to a floating firing pin in an AR-15 style weapon? I'm not talking, "it's theoretically possible under such and such circumstances", or "uncle ben heard of a guy whose rifle blew up when xxx" but hard fact that a slamfire was caused by a floating firing pin in the absence of a faulty trigger group, or other malfunction. I recognize the theoretical mechanism of such a malfunction given the design, but am extremely skeptical, (emphasis on extreme) that it is anything but a theory. I'm no armorer with millions of rounds under my belt on hundreds of different examples so I'm really asking.

I've seen it in person. It was an AR10 in 6.5 Creedmoor shooting factory Hornady ammo. I was with my buddy at a range confirming his zero before a class. He had the gun pointed at the target and hit the bolt release to chmber the round. As the bolt slammed home the round went off. Fortunately the rifle was pointed in a safe direction and if I recall the round actually landed on paper. We grabbed the case after it ejected and found the firing pin had actually pierced the primer. Our best guess was that the primer had a faulty cup and it must have just been very thin. The rifle was fine and we didn't have another issue after that.

 

[mtrmn]

I have had a total of ONE round fire when the bolt catch was released to chamber a round. Whether it was a slam fire or the hammer fell when the bolt slammed home I do not know. Of course the hammer was cocked again after the gun cycled so no way to tell. I do know that was the first time that round was chambered. Never been able to duplicate it with several hundred rounds since, and no unusually deep indents from the firing pin. Brass appeared normal and the bullet hit the ground about 30 yds downrange.

 

[-Nick-]

BR primers are a waste of money in gas gun too.
Cheers.

That's not true. Like any cartridge it depends on your desired effect and accuracy. If I'm using a match barrel on a semi-auto like a GAP-10, JP LRP 07, ect then there's no reason not to use a BR primer if it could enhance the consistency in powder ignition of my load.

 

[crankbait]

No issues after 1,000 rounds of M80 ball in my DPMS Gen2 Recon. None. Do not use the Gen 3 PMAG.

 

[Layton]

Went to the range today and manually cycled the same round 10 times. It didn't go off until I pulled the trigger on the 10th. I'm using BR4s. Very unscientific but good enough for gov work.

L

 

[M25BeastShooter]

Never had an issue with re-chambering cartridges but you should NEVER load single rounds straight into the chamber and let the bolt close, I've seen quite a few AR's in National Match and AR-10's on the bench "slam fire" loading this way. Always load from the magazine or at least lay the cartridge on the follower. This will at least slow the blot and reduce the inertia in the firing pin

 

[Layton]

I just went through over 1000 rounds single feeding with a block and I've yet to have a slamfire. Maybe I'm just lucky.

L

 

[crankbait]

Went to the range today and manually cycled the same round 10 times. It didn't go off until I pulled the trigger on the 10th. I'm using BR4s. Very unscientific but good enough for gov work.

IMHO the BCG is overlubed. Pull it out, wash it all down with solvent and dry with compressed air. Reassemble. Put one or two drops of lube on the cam pin. Put a very light film of white lithium grease on the four external rail lugs of the BCG and on top of the charging handle.

DPMS Gen 2's work better drier than wetter from my own personal experience. It's a fantastic gun.

 

[Layton]

No, I'm saying I didn't have a slamfire and the round still went off when I wanted it too after 10 cycles. My BCG does need cleaning though.

 

[-Nick-]

Never had an issue with re-chambering cartridges but you should NEVER load single rounds straight into the chamber and let the bolt close, I've seen quite a few AR's in National Match and AR-10's on the bench "slam fire" loading this way. Always load from the magazine or at least lay the cartridge on the follower. This will at least slow the blot and reduce the inertia in the firing pin

I agree but that is more common with M1A's than it is with AR's...

 

[Regalkismet]

Too much lube on an AR is akin to having too much fun.... Just not very likely.... Fact is most people under lube.... AR15's and 308's function better wet.... All AR15's and 308's do this as previously stated.... Due to the free floating firing pin.

 

[pawprint2]

There was a lot of talk about this a few years ago specifically in regards to the M1A, in fact some were putting out that the use of 210M primers were dangerous, when reloading for the M1A, due to their [210s] relative softness. There may have been an out of battery ignition, with rounds loaded with 210M primers, but not likely do to the "softness" of the 210's but what is far more probable was that it was do to "high seating" of the primer itself. Springfield Armory was actually including several articles and their own take on it with M1As. I don't know if they still do or not, but they did for a while. Regardless of your weapon system, high seated primers are a NO-GO! Other than that, it's normal. I've loaded many 1000's of 210M primers and fired them from various M1As, no out of battery ignitions yet.

 

[EXTREMEPREJUDICE]

There's no danger as long as I have control of the weapon and it's pointed in safe direction.

Thank you!

 

[Steelhead]

BR primers are a waste of money in gas gun too.
Cheers.

That's not true. Like any cartridge it depends on your desired effect and accuracy. If I'm using a match barrel on a semi-auto like a GAP-10, JP LRP 07, ect then there's no reason not to use a BR primer if it could enhance the consistency in powder ignition of my load.

I've used Federal Match primers for years in my semi-auto match grade rifles, like the GAP-10 and other AR-15 types. Never had an issue. I use them for consistency also.

 

[Hollywood 6mm]

Went to the range today and manually cycled the same round 10 times. It didn't go off until I pulled the trigger on the 10th. I'm using BR4s. Very unscientific but good enough for gov work.

IMHO the BCG is overlubed. Pull it out, wash it all down with solvent and dry with compressed air. Reassemble. Put one or two drops of lube on the cam pin. Put a very light film of white lithium grease on the four external rail lugs of the BCG and on top of the charging handle.

DPMS Gen 2's work better drier than wetter from my own personal experience. It's a fantastic gun.

In my experience, keeping the gas rings lubed is more important than the cam pin, and both are more important than pretty much everything else in the BCG in terms of lube.