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

[They_Call_Me_Riggs]

Hello everyone, I'm new to this site and thought I'd see if y'all could help with a malfunction that's occurring.

These are the specs of my rifle:
Double Diamond Law Enforcement Glock Magazine dedicated 9mm lower
Double Diamond Law Enforcement Bolt carrier
Geissele Automatics Super 3 Gun trigger
5 inch barrel with Gemtech Tundra
Heavy Buffers 11.5 ounce buffer with Wolf buffer spring

Now the issue I'm having is when firing the weapon occasionally the hammer will not be set but there will be a live round chambered. When I manually charge the weapon multiple times and dry fire/reset the trigger it works properly. When using hotter loads it seems to maybe happen more often. I usually shoot 147gr with VV N-320 powder. This occurs when a lighter buffer is in the weapon as well. I would think it was short stroking but If it was I wouldn't think it would be able to load another round. Any help would be extremely appreciated. Thanks in advance


UPDATE :

Well today was an extremely long day at the range.. A lot of bullets and a lot of wrench work..

I began with the lighter spring and hotter loads. The weapon functioned slightly better. But still failed to set the trigger occasionally. Then I loaded my 147gr hand loaded sub sonic rounds. First shot the gun failed to set the trigger for the second round. So I began to lean waaaayy more towards a blowback issue. Barrel being to short and building up too much.

So I remove the suppressor. The weapon cycles perfectly with every single load I put through it. I then replace the Geissele trigger with my Timney. I spun the suppressor back on and it did the malfunction more often. I then replaced the Timney with a factory trigger system. Weapon operated perfectly with every load ran through it suppressed.


My theory for this malfunction is this. Either the weapon is short stroking or the bolts out running the trigger. I believe with the factory trigger it has more of a tougher/stronger reset then the Timney or Geissele. Because if it was an issue with it having the wrong hammer it would do the same unsuppressed. So it seems ill be running this horribly heavy factory trigger until I can find a trigger assembly that has a super tough bite on the reset.

Thanks you guys for your help and I hope this issue helps someone else out. If you have anymore input please add it.

 

[RiverBend]

Got to be the trigger if you have a pistol BCG & pistol buffer, did it come with the Geissele or did you put it in. If its new, I'd call them about replacing it.
I had a Rock River 9mm upper & DTI lower, and it had a reg buffer (556) and that caused some issues & made it cough up a few hairballs.
Good luck it'll work out.

 

[They_Call_Me_Riggs]

I'm starting to believe its the trigger as well. I just recently purchased the Geissele and this has been the only trigger I've fired the weapon with. It's just weird to me how I can dry charge, fire and reset the trigger with no issues. But as soon as its under life fire conditions it has the issue. That's the only reason why I haven't blamed the trigger 100%... Thank you for your info sir

 

[Zombie Ninja]

Welcome to the ODT!
I would pm laxguy and ramroddoc. Those guys know their stuff on these.

 

[gagtoe]

Try a heavy buffer, it will give the trigger more time to reset.

 

[gagtoe]

I'm running a DPMS parts kit, heavy buffer, and about 2 dollars in quarters in the buffer tube with a 5 inch barrel.

 

[Laxguy59]

Try a heavy buffer, it will give the trigger more time to reset.

at 11.5oz he is pretty heavy as is. I may actually drop some weight on the buffer. Is this happening while suppressed and unsuppressed? I've heard the 13oz buffer is too heavy while unsuppressed, so maybe a similar problem?.

I run a factory cmmg lower with the cmmg 9mm buffer and RRA buffer tube.

What bolt are you using? ramped or unramped?

 

[They_Call_Me_Riggs]

I haven't tried unsuppressed yet. I'm using a custom ramped bolt from Double Diamond Law Enforcement Supply. I might try and put a lighter spring in and see if it helps. It bump fired way too easy with the 5.4 ounce from Spikes Tactical and caused the hammer to not reset more often. I then replaced it with the 11.5 ounce. It's just weird to me it's able to pick a new round up but not set the trigger and only does it under load. I wish it would do it under dry fire conditions so I could just blame the trigger and be done with the issue lol

 

[Laxguy59]

I haven't tried unsuppressed yet. I'm using a custom ramped bolt from Double Diamond Law Enforcement Supply. I might try and put a lighter spring in and see if it helps. It bump fired way too easy with the 5.4 ounce from Spikes Tactical and caused the hammer to not reset more often. I then replaced it with the 11.5 ounce. It's just weird to me it's able to pick a new round up but not set the trigger and only does it under load. I wish it would do it under dry fire conditions so I could just blame the trigger and be done with the issue lol

well I'm not sure the 9mm has to travel as far back as a 5.56 bolt, so short stroking may be easier for it to do and still pick up a round, I would try a lighter bufferspring, but a very peculiar problem.

 

[RamRoddoc]

I haven't tried unsuppressed yet. I'm using a custom ramped bolt from Double Diamond Law Enforcement Supply. I might try and put a lighter spring in and see if it helps. It bump fired way too easy with the 5.4 ounce from Spikes Tactical and caused the hammer to not reset more often. I then replaced it with the 11.5 ounce. It's just weird to me it's able to pick a new round up but not set the trigger and only does it under load. I wish it would do it under dry fire conditions so I could just blame the trigger and be done with the issue lol

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.