Just to note im not new to firearms, or the ar platform. After i liked the experience trying out a psa ar15 pistol i went to try out the ar9 platform from them. I got a 16"upper and a px9 lower from psa, im about to go fire it for the first time but i read of quite allot of issues with out of battery det. , fail to feeds etc. Lots of advice on changing parts like buffers etc. Im a bit off put by that, wondering if the g4 bolt/upper has solved these issues, or should i start modifying, or maybe just get into a different brand. Also wondering what mags run best with the psa ar9 lower, ive already noticed some failure to feeds with the gun cycling it just to test, pushing the bullet back into the case using amend 2 and pmags. (That is what prompted me to look into it and find all the issues) thanks!
Ar-9s are a tricky thing. With it being pure blowback even different ammo can affect the way it functions. I have the colt style psa lower, and i had to use a heavier buffer and a buffer spacer.
I have a 10.5 GEN4 upper and use an PSA PX9 lower that takes “glock” style mags. the lower has standard AR15 lower parts and I have had no issues with it. I use Pmag 15 and 33 round mags with no issues.
the upper did have a few issues before I realized that the BCG needs plenty of lube. and by this I mean you lube it until you think there is enough and then put some more on.
as far as ammo goes it did not like some of the longer higher grain hollow points, any thing 115 grain FMJ bullets it eats fine.
My 10.5" gen4 upper shoots everything I have tried in it, inluding reloads consisting of 158gr .357 cast semi wadcutters. I did install a buffer spacer and 308 buffer spring, not because I was having problems more because I am loading very hot ammo. Mine loves hot loads of accurate no7. It is extremely accurate even to 100yds with a cheap red dot sight.
Are you sizing your cast bullets to .358 or something else? Are you powder coating them or using a more traditional lube? How’s your accuracy with cast?
I have the 10.5 psa upper with px9 lower and have tried alot of different loads to see what it likes best. To my surprise, it likes 147 gr round nose alot. The 147 hp has trouble feeding because of how square the chamber face is. 124 gr anything seems to work and cycle good. 115 gr xtp loads feed and function the best, it just chews em up. As far as mags go, the original glock mags are trash, i mean they are built well but doesnt seem to work as good as magpul if they are fully loaded. They work if you take 3-4 rounds out from full capacity. The magpul 27 round are my go to for this gun, not one feed failure, even with the 147 grain hp’s. It also really likes 115-124 grain +p ammo. I think the heavy bcg likes the extra ummph! Hope that helps someone, despite little feed failures at first and having to tighten the buffer tube, this thing is solid and i would trust it to take care of night watch any day. Psa px9 gen 4…awesome!
I had tried Magpul, PMag, and Glock mags, and I was disappointed in them all, the Glock extended mags especially because I expect better from Glock. I was about to give up on the extended mags, but then I bought some Wolff springs for the Glock mags, replaced the spring in all of the mags I already had, and it fixed the problem. More tension in the Wolff springs, it’s like night and day. After taking this gun to the range a couple of times now, with flawless results, I am convinced that this will be my go-to for home defense now, and it’s always a great time at the range.
replace the spring in your buffer not the magazines.. this platform absolutely needs an enhanced buffer to run great with any magazine.