Short barrel suppressed 9mm AR hammer not resetting consistently after firing

[They_Call_Me_Riggs]

The hammer has to have the appropriate curve radius or it will not function with a ramped bolt correctly. The DPMS style hammer is typically good to go a notched hammer (Rock River) or specialty hammer will often cause you problems.

You can use a 9mm AR hammer with an unramped bolt and forgo the issue but then it would be dedicated to 9mm and you couldn't swap .223/5.56 uppers without changing the hammer.

I'll try to post picks later but your issue is the hammer and I'll bet money on it.

sounds pretty legitimate to me sir.. Here's some pics of the Geissele trigger in the gun, spare hammer assembly that came in the lower and DDLES bolt carrier. Let me know if the spare hammer is like what you've mentioned... Thanks for your input

 

[RamRoddoc]

Yes,

Put the DPMS style hammer (one in your fingers-pic) back in and she should run fine with your ramped bolt.

 

[bluesman2a]

I've been chasing this type of issue as well. I think these guys are pointing you in the correct direction with the hammer.
On mine, the issue was the buffer. I started with a CMMG dedicated 9mm lower/carbine upper, which came with the standard carbine length buffer in 5.6oz. Then picked up a Heavy Buffers 8.5oz (longer than carbine norm). While I was at it, I found a cheaper Spikes 9mm buffer to run in my other 9mm AR 7" pistol which is 7.??oz (also longer).

So I guess what I'm saying here is that if you change the hammer and still suspect the buffer, PM me, I have a couple different options I could let you trial for problem-determination.

 

[They_Call_Me_Riggs]

Thanks guys... I'm going to replace the Wolff buffer spring with a mil spec one from Spikes Tactical to see if that helps. If that doesn't fix it ill replace the trigger :/

 

[JDG.]

Hey I hope you get this working, but more importantly pics or it didn't happen

 

[They_Call_Me_Riggs]

Hey I hope you get this working, but more importantly pics or it didn't happen

bwhahahaha... I'm proud of my baby, so whenever I get the opportunity ill show it off..

 

[JDG.]

hey, you got my rifle. I like your style

 

[Laxguy59]

you bastards with your suppressors approved and DDLES lowers

 

[JDG.]

you bastards with your suppressors approved and DDLES lowers
View attachment 151053

hey thats nice. the rest is only time and money man spend lots and wait forever

 

[RamRoddoc]

That's some awesome looking machinery you gentlemen have and I'm sure more than a few sweaty teeth occurred on followers of this thread.

Good luck on trying different buffers/springs as I know you really want to retain that fine trigger you have currently but I feel it will not correct your issue. You have to understand the process of the bolt traveling to the rear and cocking the weapon. Subtle changes in the contact points of the hammer and your bolt (ramp) will affect it's function.

Your Geissele hammer is missing a huge amount of meat that contacts the bolt (ramped) surface:

The DPMS has a full arched curve without any notches cut within it. It works well with a ramped bolt:

This is a notched Rock River hammer and will not work with a ramped 9mm bolt as it renders it a single shot with only the tiny smidge of metal removed at the hammer tip.

Give us a range report and if the buffer/spring switch corrected it please give the details.