I have the CMMG colt style 9mm bolt.  Today I broke the tip off the firing pin.  So, I"m wondering if I can just pick up a regular 5.56 firing pin and use that or if I have to get a specific firing pin for the 9mm.  I know the 9mm uses the spring and 5.56 doesn't.  My spring is good.  I couldn't find this in the 9mm AR FAQ and I've been told by a guy at Brownells that they are the same so a 5.56 should work but I've read on other sites that they are different.  Not sure if the "difference" might just refer to using the spring.  Thanks if you can help.

why would you break the end off?

and the 5.56 is VERY different

look at the back end of the 9mm pin its shorter

The spring aside,. That pin looks nothing like my 5.56.

Not sure if that helps.

i dont know why!    I was actually testing some of my reloads and the Geissele SSA-E trigger in the AR for the first time.  I was shooting from the bench using bipod on front and a mono pod attached to the rear.  I was trying to put as little pressure on the gun as possible and only make contact with the grip and trigger (maybe not a good idea) to prevent myself from flinching and jerking the gun off target and the gun accidentally bump fired a couple rounds.  After getting over the shock I thought this was cool so...I was trying to do it again and did a couple times with 2 or 3 round bursts.  Not sure if the firing pin breaking is just a coincidence or has something to do with the new Geissele trigger/hammer or the bump firing or a combination of the two.

Thanks for the information on the firing pin difference.  I'm at work and don't have access to my 5.56.  I'll compare this evening when I get home.  I was just thinking that it would probably be easier to locate a regular 5.56 AR-15 firing pin locally than one specific to the 9mm.  If the 9mm is different I'll probably have to order one and I was hoping to avoid that.

Thank you.  I found some images of both and I see the difference now.

i think you can get them as low as $35

and the bump fire is fun and most likely resulted in the malfunction.

i believe this is an intentional failsafe  by the engineers to prevent bump firing or converting the action to full auto

wat.jpg

Ummmm...no it's not.

??

So far that's the most wrong thing I've read today.  It's the same pin that's been used forever in the Colt SMG.  My advice is to order a couple from RRA.  

RRA $12

Pick up a couple extra firing pin springs while you're at it, just because they are easy to loose.

This, the RRA parts fits the Colt 9mm guns.  I lost my firing pin spring earlier this year and only place I could find a replacement in stock online was RRA



 

Yeah, it's just a coincidence, you should see me bumpfire my ar45 with my sd3g or my ar9 with its SSA-e, they are a hoot to shoot although expensive unless shooting tula. No problems with my firing pins after 500+ eds. Have fun and gun on