New build. BCG won't retract fully. Gets stuck when about 2/3 retracted.

[Vegas]

I don't think anyone has been rude. 80% lowers are what they are, only as good as the person doing the finishing. Out of spec trigger parts or lower are the obvious as previously mentioned. Matter of elimination at this point.

[Iraqgunz]

I wish people would spend more time reading some of the troubleshooting stuff here and applying some of the basics rather than worrying about the latest Uber-light unobtanium gas block or super duper whizbang.

I don't think anyone has been rude. 80% lowers are what they are, only as good as the person doing the finishing. Out of spec trigger parts or lower are the obvious as previously mentioned. Matter of elimination at this point.

[ace4059]

But I built it with my Dremel.




Sorry. Couldn’t help myself.

[ClangClang]

He probably should have mentioned it is an 80% before post #10.

If I posted that it was an 80%, it's virtually certain all the responses would have been useless "it's your lower that's out of spec dude" without any other information to help the troubleshooting process.

I wanted to say, thats what you get when you buy the cheapest stuff. ..followed by a you get what you pay for rant.

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Going 80% is VERY far from the cheapest option.

There looks to be a lot of metal shavings in your picture. I would fully disassemble the lower and clean it out with acetone or alcohol and then as militarymoron mentioned put in a USGI trigger and see if you still have issues.

Those aren't metal shavings, just slight wear to the anodization which shows up looking fuzzy in my low-rez phone camera. The lower is completely clean.

[ClangClang]

It's also not my first rodeo when it comes to basic machine work. I am fairly confident that the lower was machined correctly and within spec, hence my original question. If you refer back to my "edit" on my last post, reducing the tension on the trigger set screws actually solved the issue about 95% of the way. I actually believe the trigger to be the culprit, but I don't have any spare other triggers lying around to test it. I've got some more Geissele triggers coming whenever the Black Friday orders finally show up (probably another couple weeks, according to the disclaimer at checkout) and will re-test the lower then.

I appreciate everyone's input thus far, even the non-helpful posts. I certainly knew to expect some of that when posting about an 80% lower. I wanted to try an 80% for the challenge of it. It's certainly not ever going to be pressed into use as a duty or SD/HD platform.

[daniel87]

If the trigger did fix your issue 95% then ignore what i wrote regarding your build.

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[Jmacken37]

I had something similar happen with an LMT upper that had an improperly timed barrel nut causing the gas tube to be canted. Easy to check for this by dropping the bcg into the upper. You should be able to remove it fairly easily.

I also had a "premium" PSA bcg where the bolt was stiff in the BC. After 30 round or so, it loosened up.