Home Forums Hunting & Shooting AR and Tactical Rifles Jacked up my lower assembly......gun will fire but won't cycle...please help!

I purchased a complete PSA 9mm upper and put together the lower myself. Today I was able to hit the range to give it a run but something is JACKED up!!

I can load it and fire it but it locks up. I can take the mag out and pull back the charging handle (very hard to do) to clear it. It's like my BCG is getting jammed somehow but I have no idea what I could've done wrong!

If its a new build the first thing i'd do is lube the heck out of the BCG and try again.

Did did use a 9mm buffer system in the lower?

Like Trout said, run it wet.

Did you function test the lower by itself?





Dave

9mm's take a different hammer at least Colts do.

Function test your lower is pretty easy, hammer should reset with just a few pounds of pressure and the safety should work. I think the psa is a ramped bolt, so it should use standard lower parts with a different mag catch. The hybrid uppers must be used with a hybrid lower, not sure what is different.

Lube the bolt, make sure it cycles freely in the carrier and the carrier slides freely in the upper.
Check the buffer spring and buffer to make sure they are free and the right parts for a AR9 (although wrong spring and buffer would probably cause a short stroke)

If it's locking up, probably a gas/bolt issue. About the only thing you can goof up in a lower is getting the hammer spring backwards which will cause light primer strikes.

This! Your symptoms indicate that TWR most likely has the problem area nailed.

This is a PSA 9mm Hybrid designed to take Glock mags. I just re-checked the PSA site and it states "Accepts standard AR-15 fire control groups, bolt catch, take down & pivot pins, springs & detents, safety selector as well as stock, buffer tube and grips." I replaced the triggers in my Colt 6920s with Geissele SSA triggers and used one of the factory Colt triggers for this build but that shouldn't be an issue.

Originally, I thought I messed something up with the buffer (factory KAK pistol blade kit) but it could very well be something with the trigger. Once I pull the charge handle back, I can charge it over and over normally but once I fire a shot, it binds and is very tough to charge.

check your gas key/tube fit. also make sure your gas block is seated right over the gas port.
i have one bcg with a tight gas key and it binds up like that on several tubes, but does fine on one ,so i dedicated them to each other.

wonder if your buffer is over riding the stop when you fire and it returns to battery. Then pulling on the charging handle with difficulty you put the buffer back over the stop and it stays put, so it is not as difficult on the second charge attempt. What lower parts kit did you use?

That would make sense Jimmy. Most of the springs/pins are CMMG, the trigger is Colt and the buffer/tube/spring are KAK.

Is it ejecting the fired round? If it isnt you may have to polish the chamber.

Try dry firing it and then pull the charging handle, if it locks up then your hammer is binding your bolt.

Better check the specs on that upper.

Some of the PSA 9mm uppers are only designed to work with lowers by the same manufacturer.