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Having issues with 9mm build, with the trigger not reseting.


sasquatch981

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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 by sasquatch981
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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......

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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.

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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.

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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 by StealthyBlagga
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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.

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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

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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.

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