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Gunsmithing help with 80% CNC build...

badicedog

Private
Full Member
Minuteman
Jan 3, 2010
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Guys I need help with a problem on a 80% build of mine. First a little history... This is not my first 80% builds, Ive done quite a few on an old Bridgeport mill, but this one in question is the first one I've done on a CNC. The issue that I am having is that the safety will not rotate/engage all the way from fire position to safe position. However if I remove the hammer, it will freely move 90 degrees from fire to safe. I checked the deck height to make sure it's correct. When the hammer is installed the safety will rotate about 15-20 degrees and that's it. I am using factory parts from HK and a Geissele trigger. Any help, suggestions, hints, comments and or criticisms are all appreciated. Cheers.

 
Sounds like the safety hole is a smidge too low. I had a factory lower that was like this a while back. I ended up tapering the back of the trigger down slightly until it cleared the diameter of the safety selector.
 
.....or the Geissele trigger is a smidgen too high.


Try a standard trigger.
 
What buffer retainer plug is that?
Also agree with above, have seen that issue with Timney drop in's.
 
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What buffer retainer plug is that?
Also agree with above, have seen that issue with Timney drop in's.

It's a factory Hk 416 buffer retainer. Had to wait 6 months to get it from Germany...lol
 
Thanks for all the input. I really appreciate it.. I have been itching to mill a smidge from the Geissele trigger but wanted to wait until I got feedback from the boards. Cheers.
 
lolololololol YES, I just LOL'd (made my day) :)

BTW which area of the trigger should I remove material from? i don't want to go dremmel crazy...lol
Thanks again guys.
 
What has beat the crap out of your buffer??

The buffer retaining pin is holding the buffer too far back. It stops on the pin and the bolt carrier runs free the last little bit to battery.

Either the hole is too far back or that HK416 part wasn't a great idea.
 
If the safety is not engaging, look on the SIDES of the rear of the trigger itself, sometimes the cutout on the safety itself is too narrow to allow the sides of the trigger to slip past (inside) that cutout or ears of the safety. I believe it mentions this in the directions for the trigger. The solution is to file away a small portion on each side of the rear portion of the trigger or to widen that gap in the safety, whichever you choose. Before doing that disassemble everything and see if that rear portion of the trigger even slips into the gap in the safety.
 
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