Primer dents

[lrahm]

I talked this over with ATM who stated that this would be worthy of a new thread. I carry an AR at work. I carry it in "cruiser safe" mode. None in the chamber and the safety on. Everytime I chamber a round, it leaves a small dent on the primer. I have to chamber a round at least once a week. I then started to rotate my rounds. When I approached the range instructor, I found out that I am not the only one experiencing this problem no matter which brand. I had this sinking feeling that one of these times it will discharge. The instructor went as far as running the same round through his at least 200 times, no discharge. Is there anyone els experiencing the same problem or have any malfunctions? Please don't think of me as stupid, just cautious.

 

[shibumiseeker]

It's normal for ARs. Regardless, you should be pointed in a safe direction when you chamber a round in any gun, right?

 

[lrahm]

It's normal for ARs. Regardless, you should be pointed in a safe direction when you chamber a round in any gun, right?

Always, I try to be as safe as humanly possible. We get trained on the same gun safety rules every year.

 

[bigcraig]

Normal.

Carry on.

 

[lrahm]

Normal.

Carry on.

Thanks, just can't be too careful.

 

[sloughfoot]

Floating firing pin. Not to worry.

AR, M1, M1A, SKS and many other rifles have floating firing pins.

 

[Squirt239]

had the same problem with one i built. scared the who-hockey out of me. thought for sure i had done something wrong. i then had an old timer at a gun shop tell me it's normal. i didn't like that answer so asked around to a few other smiths in the area. same song. carry on!

 

[BlueEagle]

Yep. Routine operation.

 

[jblomenberg16]

Every now and then you hear a story about a slam fire, and it usually also is reported the ammo had "Soft" primers. Not sure if there is any truth to the soft primers, but I think that on more than one occaision it has been determined that the ammo was a personal reload and the primer was not fully seated.


The dent in the primer is normal. Follow the safety rules and you should be good to go.

 

[shibumiseeker]

Every now and then you hear a story about a slam fire, and it usually also is reported the ammo had "Soft" primers. Not sure if there is any truth to the soft primers, but I think that on more than one occaision it has been determined that the ammo was a personal reload and the primer was not fully seated.


The dent in the primer is normal. Follow the safety rules and you should be good to go.

Often times it's crud in the firing pin channel.

 

[MRP2003]

Thanks for the heads up. I will pass this along to my friends

 

[jblomenberg16]

Often times it's crud in the firing pin channel.

Yep, this too. A sticking firing pin is sure slam fire waiting to happen.

 

[esrice]

Good thread!

 

[ATM]

I figured there might be some discussion on case setback, where the bullet can be driven deeper into the case by repeatedly chambering the same top round if it is not eventually cycled out.

Has anyone measured setback or know the difference in overpressure that would be typical of a rifle vs. handgun round?

Also figured there would be at least one claim that the rifle was no better than a rock without a round chambered.

I applaud the restraint.

 

[lrahm]

I figured there might be some discussion on case setback, where the bullet can be driven deeper into the case by repeatedly chambering the same top round if it is not eventually cycled out.

Has anyone measured setback or know the difference in overpressure that would be typical of a rifle vs. handgun round?

Also figured there would be at least one claim that the rifle was no better than a rock without a round chambered.

I applaud the restraint.

Thanks again ATM..... and everyone.

 

[jblomenberg16]

I figured there might be some discussion on case setback, where the bullet can be driven deeper into the case by repeatedly chambering the same top round if it is not eventually cycled out.

Has anyone measured setback or know the difference in overpressure that would be typical of a rifle vs. handgun round?

Also figured there would be at least one claim that the rifle was no better than a rock without a round chambered.

I applaud the restraint.

I remember seeing a thread on this a while back, and think that there was someone that did find some evidence of set-back and increased pressure in some pistol cartridges. I'm thinking they were looking at .357 sig IIRC.

Not sure of a study on say 5.56 in an AR. I do know that most factory ammo out there has a significant crimp on it, so it is probably unlikely the setback will be even an issue, especially on FMJ ammo in a rifle with full feed ramps.

 

[lrahm]

I remember seeing a thread on this a while back, and think that there was someone that did find some evidence of set-back and increased pressure in some pistol cartridges. I'm thinking they were looking at .357 sig IIRC.

Not sure of a study on say 5.56 in an AR. I do know that most factory ammo out there has a significant crimp on it, so it is probably unlikely the setback will be even an issue, especially on FMJ ammo in a rifle with full feed ramps.

It was a noticible dimple on each primer. It's a little scary.

 

[Hayseed_40]

Normal for there to be a dimple as people have said it is due to the floating firing pin.

Keep the firing pin channel clean. Keep the firing pin clean (all the way down the shaft). I only put a VERY light oil on the pin so that it does not gunk up.

Do you use the chamber flag that will chamber the round as you pull it out? That is the way I used to carry. Keeps it safe and chambering is one fluid motion withut using the CH.

 

[Chase515]

 

[sharkey]

Every now and then you hear a story about a slam fire, and it usually also is reported the ammo had "Soft" primers. Not sure if there is any truth to the soft primers, but I think that on more than one occaision it has been determined that the ammo was a personal reload and the primer was not fully seated.


The dent in the primer is normal. Follow the safety rules and you should be good to go.

IIRC, the Army had issues with slams fires during early testing of the AR-15 due in part to soft primers.

Also, IIRC, they had problems in the '30s with slam fires in the M1 Garand with soft primers too.