Hand-cycled a rounds: Large dimple left in primers, bullets scratced to Hell!

[rogerxd45]

my ar does the little dent also and the scratch on the bullet is from the feed ramps

[mvician]

it also does this to rounds that are cycled during shooting but you just don't notice it

[Tard]

Personally, I'd clean the chamber really well with a brush as someone else has already advised, take the bolt apart and clean/ inspect the firing pin and if it kept doing it, take it to my (good) local gunsmith for inspection.

[120mm]

Originally Posted by rogerxd45

my ar does the little dent also and the scratch on the bullet is from the feed ramps

They wouldn't be "corkscrewed" from the feed ramps. The bolt doesn't rotate until the round hits neck and leade area.

[mvician]

quit hand cycling live ammo
all you are going to do is create worries and problems with bullet setback along with the possibilities of a ND/AD

[dfalcon217]

I was having the same problem. Took (2) 10/20 round Pro Mags my rifle (600) rounds of mixed Wolf Steel Case and Rem from Wally World and needle nose pliers to the shooting bench.

Had several FTF issues, double feeding, last round popping out

After every occurrence I tweaked the feed lips on the magazines till it the problems were gone 100%. Problem solved, it was the magazine feed lips all along.

Taken from Wiki:

"An additional point of concern in the design is the inertial firing pin, a lightweight firing pin rides in a channel inside the bolt unrestrained, when the bolt locks forward during loading, the firing pin typically rides forward and impacts the chambered round's primer. In military specification ammunition and quality civilian ammunition, this is not normally enough to fire the round and only leaves a small "ding" on the primer, with more sensitive primers or improperly seated primers, this can cause a slamfire during loading."

[Mercmar]

I'm using a titanium firing pin and still get little dimples. I have polished my feed ramps, though, and don't seem to have any accuracy problems. I'd think that deep scratches on the bullets would affect accuracy.

You don't have to take the barrel off to look at the feed ramps. Just take the upper off of the lower.

If the previous owner shot much lacquered Wolf ammo through it, I'd think that the chamber's fouled and could use a good scrubbing. A rough chamber would exacerbate the dimpling of the primer.

[mvician]

Like I said 2 posts up.........QUIT hand cycling live ammo !

This was taken from the Ammo Oracle

Q. I chambered a round in my AR and then unloaded it later. The primer has a small dent in it, apparently from the firing pin. Should I be worried about this? Won't that cause a slam-fire? Should I switch to a Titanium firing pin?
A gas-operated semiautomatic operates on gas bled from the barrel. This gas is channeled to the bolt operator, which blows the bolt open and ejects the spent shell casing. A heavy spring then returns to bolt carrier to the closed and locked position on the next round. In the case of weapons with free floated firing pins (SKS, AR-15, etc.), the inertia of the firing pin carries it forward and it strikes the primer as the bolt closes. (The "slam"). Generally this will dimple the primer and leave a small indent. This isn't anything to worry about as primers for centerfire .223 and 5.56mm are pretty "hard" and aren't likely to be set off by this impact.
Early M-16s had a problem with slamfiring because of the firing pin design. Eventually Colt redesigned the pin to be lighter and therefore carry less energy into the primer.
Slam-fires are pretty rare in modern ARs provided they are well maintained but they can be caused by a broken or protruding firing pin, foreign matter on the bolt face that is carried into the primer, foreign matter in the firing pin assembly that prevents it from retracting sufficiently, overly soft or poorly seated primers, or other malfunctions.
As for titanium firing pins, they are probably not worth the headache. Indeed they are lighter and may reduce the already small chance of slamfires, but titanium also does not handle impacts well and can be brittle. A broken or cracked titanium firing pin is a lot more likely to cause a slamfire than a regular pin.
It should be noted, however, that repeated chambering of the same round increases the likelyhood of a slamfire, or of a hangfire (slow to ignite) or misfire (failure to ignite) due to damage to the round's primer. If you chamber and clear your rifle on a regular basis, make sure you change out the top round so that you don't rechamber the same round more than once or twice.
Finally, always point your rifle in a safe direction when chambering live ammo. As with any machine, there is always the possibility that something will go wrong and the round will fire. If you are chambering your home-defense gun, ride the charging handle and use the forward assist to lock the bolt forward, always keeping the muzzle pointed in a safe direction.

[120mm]

Originally Posted by dfalcon217

I was having the same problem. Took (2) 10/20 round Pro Mags my rifle (600) rounds of mixed Wolf Steel Case and Rem from Wally World and needle nose pliers to the shooting bench.

Had several FTF issues, double feeding, last round popping out

After every occurrence I tweaked the feed lips on the magazines till it the problems were gone 100%. Problem solved, it was the magazine feed lips all along.

On mixing Wolf and brass, it is generally considered a bad idea to shoot Wolf and THEN brass. The steel cases do not expand like brass, which allows residue to build up in the chamber, which the follow-on brass cartridges expand into the crud, and possibly not extract.

Just a tip.

[rupert]

I would like to add....When I was in Iraq, I reused the same round that I chambered over and over and over again and had no problem.

The only way I did not reuse that same round is if I lost it when i cleared my weapon at the game or i shot up some ammo when I was in sector.

I would say I’ve used the same round 10 times to load. There was a dimple in the primer, I really did not care though. I always pointed in safe direction (clearing barrel) to clear my weapon.