sasquatch981 Posted March 29, 2016 Share Posted March 29, 2016 (edited) I posted this on AR15.com as well, but thought I would get as many ideas as I can. I am building a new 9mm SBR upper, and have issues with the trigger resetting. I had an old RRA 9mm 16" upper that I recently sold and I wanted a 9mm again so I decided to build. Parts are: Aero Slick Non-forward assidt upper. MAS Defense Ramped Bolt (for Colt, and Glock Pattern) VM-Hytech Lower (the old lower from the RRA upper) Hahn Bottom Loading block (super tight fit needs to be tapped into place with dead-blow hammer) Jard Adjustable Trigger KNS Pins Now most of the parts are from the old RRA except the upper, bolt, and block. The block should not be an issue as that does not have anything to do with the trigger. That leaves the upper and the bolt. When I cycle bolt it will reset the trigger in (3) different lowers. However, it will not reset if the trigger is held back after the break of the shot. Thinking it might be the trigger (not sure why nothing changes from the RRA set-up), I swapped the upper onto the other (3) lowers and the same thing happens. The trigger will not reset if held back. I was thinking maybe because the ramped bolt was set for glocks as well, that might be the problem, but that "should" not be an issue. Any ideas? [:/] Edited March 29, 2016 by sasquatch981 Link to comment Share on other sites More sharing options...
ShooterSteve Posted March 29, 2016 Share Posted March 29, 2016 If your Jard has a small set screw on the bottom of the hammer, make sure it is all the way in, and not dragging on the bottom of the receiver. Not sure if this could be your problem, but it doesn't take much backout of the screw to stop things. If the pin hole is drilled a couple thousands low, and the screw is protruding a little it will shut things down. This problem usually only occurs in the middle of a match...... Link to comment Share on other sites More sharing options...
dauntedfuture Posted March 29, 2016 Share Posted March 29, 2016 At one point i had an AR 9mm SBR upper and it would do the same thing. I was using a GI trigger. If i remember correctly what was happening is that the "tail" on the back of the hammer was contacting the rear of the trigger / disconnector and as such would not completely reset. I cut the tail off the back of the hammer and it fixed the problem. Link to comment Share on other sites More sharing options...
Shooter115 Posted March 29, 2016 Share Posted March 29, 2016 Is the trigger functioning correctly with the upper removed? Is the disconnector catching the hammer? The pre-travel adjustment on the Jard triggers is very sensitive, 1/16 of a turn too much and the trigger sear won't catch the hammer. Link to comment Share on other sites More sharing options...
StealthyBlagga Posted March 29, 2016 Share Posted March 29, 2016 (edited) Check your disconnector is assembled properly... some triggers can be assembled with the disco spring upside down, for example. The installation instructions should include a safe function test; make sure it passes. Also, if your lower receiver has an "upper tensioning screw" intended to remove play between upper and lower, take that crap out and pitch it in the trash - it can cause a lot of problems with some triggers. Edited March 29, 2016 by StealthyBlagga Link to comment Share on other sites More sharing options...
sasquatch981 Posted March 29, 2016 Author Share Posted March 29, 2016 Like I said above, the lower works fine with other uppers in place. Since this is the registered lower I swap it around. It works fine on all the the others, just not the 9mm. I am pretty sure is has something to do with the bolt, as with .223 bolts it resets fine. If it were the trigger set screw, or the disconnector, I would assume it would cause problems with the other uppers as well. It is only with the 9mm that it does not reset after the intial break. If I release the trigger completely after the shot it will reset. Link to comment Share on other sites More sharing options...
fishsticks Posted March 29, 2016 Share Posted March 29, 2016 So is the hammer "standard" or a bobbed/speed version? Link to comment Share on other sites More sharing options...
sasquatch981 Posted March 30, 2016 Author Share Posted March 30, 2016 Link to comment Share on other sites More sharing options...
fishsticks Posted March 30, 2016 Share Posted March 30, 2016 Disclaimer - I'm no expert. Love it or hate it, AR15.com does have some good technical information. I'd try this thread - https://www.ar15.com/archive/topic.html?b=3&f=15&t=481780 or this one - http://www.ar15.com/forums/t_3_15/108261_9mm_AR_FAQ.html Failing that there is an entire technical sub-forum here http://www.ar15.com/forums/f_3/15_Rimfire_and_Pistol_Calibers.html Link to comment Share on other sites More sharing options...
Full mag Posted March 31, 2016 Share Posted March 31, 2016 Just ran into this same problem and it was the hammer profile. The first hammer that was in the gun, had a AR 15 hammer and wasn't resetting because of the notch so when I put a M-16 hammer and all problems solved for my 9mm AR build. I hope this helped http://www.ar15.com/content/legal/ar15-m16parts/hammer.gif Link to comment Share on other sites More sharing options...
moto727 Posted April 2, 2016 Share Posted April 2, 2016 its the block. buy a dedicated lower. the block is pushing up on the bolt so the hammer is not being fully contacted so it isnt resetting. i played this game to with the hahn block. Link to comment Share on other sites More sharing options...
Full mag Posted April 4, 2016 Share Posted April 4, 2016 Ran about 200 rounds through mine yesterday with no problems and it has a drop in block. Running 147gr blue Bullets, that thing is a blast to shoot especially suppressed. Don't give up, you will enjoy the hell out of it. Link to comment Share on other sites More sharing options...
sasquatch981 Posted April 12, 2016 Author Share Posted April 12, 2016 Ironically enough, it was the bolt. Put in an un-ramped colt bolt, and trigger reset each time. Thanks for all the help guys. Link to comment Share on other sites More sharing options...
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