Problem with 9mm AR - have tried everything..

[Private]

10.5" AR .. 9mm barrel, RRA lower with mag block.

Here is the issue, the rifle is not consistent with the issue. When shooting I am experiencing the problems at different time. Sometimes after 3 rds, and sometimes every other round.

When I start firing ,the rifle will fire, eject the spent round, cycle and chamber another round but will not reset the hammer. Sometimes it will. When I pull the charging handle to chamber another round and #### the hammer the round that was in the chamber , but did not fire, shows a slight indent on the primer. But the trigger doesn't move, it is stuck back.

My guess at what was happening was the rifle was recoiling enough to eject the round but not enough to #### the hammer. , or. For some reason the hammer is not catching on the trigger sear

Has anyone experienced this issue

I am currently using a heavy buffer, changed that out with no help

 

[heckler]

sounds like you need a hammer mod. or "spurless" version.

 

[Private]

Can you please explain

 

[heckler]

Yes, 9mm bolt has no cutout in the center like a .556 bolt carrier. It pushes the spured(with hook on end) down to long for the timeing of the sears to work correctly. This pic of a timmney is simillar to a spurless hammer.

[/IMG]

 

[667]

Sounds like whoever put the gun together overlooked thw hammer issue...

Try a common run of the mill mil-spec non fancy-schamcy hammer.

 

[Paulinski]

or get your bolt ramped and use standard ar15 hammer

 

[just having some fun]

Problem with 9mm AR - have tried everything..
10.5" AR .. 9mm barrel, RRA lower with mag block.

What ammo -----> g of bullet ?

factory ? brand

reloads ?

 

[fango]

9mm ARs can be very temperamental and require the right touch. Once they have all the quirks worked out they are very reliable and a ton of fun.
What kind of mags? Are they the 10 round pistol mags from Questar? If so only load them up with 5 rounds and break them in slowly over 2 to 3 sessions then add an extra shot per mag per session. Out of 8 mags none worked right first time out and now all work reliably at full capacity.
Also, this firearm requires very hot ammo. You are best off loading your own. Use the load data manuals and follow them religiously. For legal reasons I will NOT recommend a max load but that one would work the best. What you can do is load a heavy bullet (147 gr) to achieve plenty of back pressure. If you can get it Military IVI ammo works great!
Until all the parts are broken in properly don't limp wrist, hold it tight. And use a flashhider until it is broken in and no compensators.

 

[sky52]

Run a mil-spec M16 hammer, ramped the bolt. Uses standard weight buffer spring and buffer with the Spike's Tactical buffer stop. ANy gunsmith should be able to ramped the bolt for you, if not i know Dlask out here in vancouver does it for $50.

My 9mm is a franken gun and *knock on wood* runs on even low powered ipsc load. My set up is a spikes tactical lower on spikes block, cmmg ramped bolt. Regular spikes tactical LPK with its 9mm buffer stop, and regular carbine buffer.

Hope this helps you out

 

[Private]

I have been using both 147 g and 115 g ammo. Both seem to have the same issue.

Here are some of the pictures of my hammer.. Can anyone identify any problems just from the pics?

 

[Paulinski]

Looks like standard AR hammer.

You need to get your bolt ramped to use the hammer you have or you need 9mm hammer.

 

[Private]

Can I keep all existing springs and just replace the hammer? Or do I need a complete new lower parts kit?

 

[Paulinski]

Just the hammer...

ETA - if you have an access to a gunsmith I would rather have the bolt ramped...Unramped carrier cocks the hammer really early - stressing the hammer pin and possibly damaging the hammer pin holes in the lower....

IMHO - ramped bolt and standard AR hammer is the way to go for 9mm AR....

 

[Leg]

Looks like standard AR hammer.

You need to get your bolt ramped to use the hammer you have or you need 9mm hammer.

There is no need to ramp the bolt with an M16 or no notch hammer. Doing so may smooth out the function and reduce stress on the parts but it is not required.

A Colt 635 uses the exact same bolt as the semi version with an M16 trigger mech.

It sounds like the hammer doesn't always reset. This could be due to problems with the disconnector or sometimes the screw that holds the pistol grip can exert pressure on the trigger mech.

I'd try swapping out the disconnector and backing out the screw in the pistol grip and see if that effects anything.

 

[Private]

I will try both of these.... In the meantime, I do not have access to a gunsmith and do not want to purchase the 200 ramped bolt. I will try the 20 $ 9mm hammer and see if this does the trick... Only problem is I can't find them online, or a place that will ship them to canada... Anyone know a place?

 

[Kindly Old Coach]

Questar appear to have Rock River Arms 9mm hammers. $32.

https://shopquestar.com/shopping65/shopexd.asp?id=383&bc=no

They're in Ontario, so they might ship to Canada.

 

[Leg]

There is nothing wrong with the hammer that you have in there now. Putting in a 9mm hammer isn't going to do anything except lighten your pocket.

There is also no need to ramp the bolt. It might be nice to do down the road but it won't do anything to sort out a trigger mech that doesn't reset.