I have a PSA'd Lower that is converted... the thing is, the magwell adaptor ( also PSA ) is not a in or out thing... ( it is a Colt Pattern version. )
I drops in from the top and you need to remove the bolt catch to do this.
As for function... it has been very reliable with my PSA 9MM Hybrid upper.
Other details just for an FYI... PSA Blem AR lower, Carbine stocked, Complete PSA 16" FF tube upper, 7.5ish oz extended 9mm Buffer, Tubbs .308 Flatwire recoil spring, And an ALG trigger, with some JP springs.
The heavy recoil spring ( yes it is a .308 spring weight ) and heavier buffer really helped tame its "bark and blast" from the ejection port and its over-enthusiastic cyclic speed.
You can run a standard carbine buffer spring and buffer... but the blow back cycles pretty danged fast. And as mentioned earlier, the bark and blast from the ejection port is noticeably increased quite a bit..
It functions very, very well after some minor feedramp polishing. ( de-burring the sharp snagging edges. )
Only some very cheap crappy 9MM ammo produced issues feeding and it was the ammo, not the firearm... and the SIG V-Crown ammo's HP was to damned wide for 100% reliable feeding. I tried 129 different OEM ammos through it... and have the chrono data if any one is interested.
Also be aware ... not all triggers will function properly with a ramped 9MM BCG, typically the reset doesn't work correctly.
If you have any questions .. feel free to ask.
Accuracy is quite good considering the 9MM round... no problem keeping 10rds in a fit sized group at 100yds with the RD sight and a 6x magnifier from the bench.
