Indentions in primer???

[Gun Chooter]

I noticed when unloading one of my ar mags today that the top round had a slight endention in the primer from the firing pin. This is a live round so it caught my eye. My assumption was that this round had been loaded into the chamber and when the bolt stopped behind the round in the chamber, the firing pin lightly smacked the primer causing this dent. To test my theory, I put the mag back in the rifle with a fresh round in the top of the mag. The bolt was held open in the rearward position. I let the bolt drop to take the top round and chamber it. Pulled the mag and unloaded the round to inspect, and sure enough there was a slight endention in the primer. Anyone else experience this? Is this dangerous?

 

[sloughfoot]

Floating firing pin. Continue on with your life.

 

[Mgderf]

Yeah, what he ^ said.
It's somewhat normal, as long as it's not setting it off...

You could try replacing the firing pin if it really bothers you. They're only a few bucks, and a cinch to change.

 

[Gun Chooter]

Yeah, what he ^ said.
It's somewhat normal, as long as it's not setting it off...

You could try replacing the firing pin if it really bothers you. They're only a few bucks, and a cinch to change.

Id rather not find out that it's a problem by having a unexpected round pop off. What would be different about a new firing pin that would prevent this from happening?

 

[easy]

A new firing pin won't make a difference. It's a design characteristic that's a proven design. It is what it is.

 

[Mgderf]

A new firing pin won't make a difference. It's a design characteristic that's a proven design. It is what it is.

It shouldn't make a difference, but I've seen stranger things out of "spec".

 

[Mgderf]

Id rather not find out that it's a problem by having a unexpected round pop off. What would be different about a new firing pin that would prevent this from happening?

Having an unexpected round going off is something you should be constantly aware of with an AR platform. They don't happen often, and shouldn't happen at all, but Google the term "slam-fire".

 

[Sniper 79]

Floating firing pin. Be aware of it and it is not a problem. When out hunting I slowly close the bolt and give the forward assist a tap muzzle in a safe direction.

If you hand load you can buy CCI mil spec primers which are harder material. I hand load and use Winchester and have never had an issue although I am aware of it and in certain instances go easy on the bolt closure. AR rifles are not the only rifles like this.

 

[Gun Chooter]

So is this something that is common in most ARs then? What is different about the ones that don't? I consider my safe gun owner and am always aware of the state and direction my fire arms are pointed, but why should an unexpected shot be something to to be constantly aware of in an AR platform? I'd think this would be something to deter most people from the platform. It would me at least.

 

[UGaARguy]

So is this something that is common in most ARs then?

It happens in all ARs, and several other semi-auto rifles. The firing pin floats freely in the channel, and that's why it will lightly indent the primer when the bolt closes. There isn't enough energy transfer to ignite the primer though.

why should an unexpected shot be something to to be constantly aware of in an AR platform?

It isn't. Just don't go smacking the butt plate into things with a round in the chamber.

 

[Gun Chooter]

It happens in all ARs, and several other semi-auto rifles. The firing pin floats freely in the channel, and that's why it will lightly indent the primer when the bolt closes. There isn't enough energy transfer to ignite the primer though.

It isn't. Just don't go smacking the butt plate into things with a round in the chamber.

That makes sense, not sure why I didn't notice it until now, just kind of freaked me out. Thanks for the input all

 

[red_zr24x4]

Floating firing pin. Continue on with your life.

Listen to the man

I hand load and use Winchester and have never had an issue although I am aware of it and in certain instances go easy on the bolt closure. AR rifles are not the only rifles like this.

ME too, I've loaded 1000's of rounds for AR's ,M1'S, M1A's and haven't had a slam fire yet.

It happens in all ARs, and several other semi-auto rifles. The firing pin floats freely in the channel, and that's why it will lightly indent the primer when the bolt closes. There isn't enough energy transfer to ignite the primer though.

Yep, AR, M1 Garand, M1A, But the M1 & M1A have a safety bridge and a "hook" on the end of the firing pin, but slam fires can still happen.

 

[Kirk Freeman]

Having an unexpected round going off is something you should be constantly aware of with an AR platform. They don't happen often, and shouldn't happen at all, but Google the term "slam-fire".

Not just with ARs, but 870s too. Hey, have I told you guys about the 870 in Alabama?

 

[joe138]

The biggest problem with the floating firing pin is that repeated strikes on the same primer can cause the primer to go dead and the round not fire. It is important to not rechamber the same round repeatedly.

 

[padawan]

You mean like this...
From a 10oz buffer and extra power jp buffer spring.

There was an earlier thread a few weeks/months ago about this...

 

[Gun Chooter]

You mean like this...View attachment 35446
From a 10oz buffer and extra power jp buffer spring.
There was an earlier thread a few weeks/months ago about this...

The picture is almost identical to what Im experiencing.
I didn't expect this to be something so common, I'll search next time.

 

[Kirk Freeman]

I didn't expect this to be something so common,

Common? Let me draw you a picture.

See is this helps, GC: https://www.youtube.com/watch?v=D8Q4kHuzRSA

Here is how the good slam fires work: https://www.youtube.com/watch?v=_cv7BI3wGWA

Remember, every time you load or unload the firearm, it may discharge even though your finger is nowhere near the trigger. Sand barrels for all!

 

[Gun Chooter]

Common? Let me draw you a picture.

See is this helps, GC: https://www.youtube.com/watch?v=D8Q4kHuzRSA

Here is how the good slam fires work: https://www.youtube.com/watch?v=_cv7BI3wGWA

Remember, every time you load or unload the firearm, it may discharge even though your finger is nowhere near the trigger. Sand barrels for all!

Not sure Im following your artwork but the videos make sense. Thanks for the links.

 

[padawan]

Try inserting a round in the chamber by hand, then let the bolt drop. The 'floating' firing pin hits the primer with a little more force. If you let the bolt feed the round from the mag, the round is already moving with the bolt. Now what if you had a round where the primer wasn't seated all the way in the pocket. Hmmm.

 

[throttletony]

I think they make lightweight firing pins to help avoid slam fires.
i don't know if there are any reliability issues.
Anyone familiar?