Hello,
I have a PSA G4-9 upper with a PSA GX-9 lower, AR9 Buffer and spring, and PSA AR-15 FCG. I’m running into an issue where it (i believe) hammer follows or “short strokes”. I’ve made sure that the weapon is cleaned and that everything is moving as it should. there is a small “hump” towards the top of the hammer face (see photos), and it does become more resistant to charging as the bottom of the bolt meets the hump on the hammer. I noticed the same thing on my fully PSA AR-15, but it functions just fine. Is this an issue with my buffer system being to stiff, or FCG?
Thanks for the help!!!
forgot to mention this is happening with 115 grain ammo
I would start with the buffer. Post a picture of it. And what brand ammo? Also, these were factory built and you just mated the two together?
welcome to the forums @croninbryce !!!
@GuitarGuy i assembled the FCG myself as well as the buffer assembly. i double triple quadrupole checked that it was put together properly. i typically use 115gr magtech or other cheap fmj ammo.
Assemble everything and with your finger push the bcg back into the buffer tube (through the ejection port). See how far it goes back. It could be overtraveling. That can be fixed by using a spacer or quarters (although you have an extended 9mm buffer).
overtraveling can cause hammer follow?
see photo. the face of the bolt sits at the furthest back part of the ejection port opening
Just crossing items off the list. Bolt bounce, traveling too far, etc. Can all cause hammer follow and are associated with the buffer. Since its pure blowback it can be finicky and stuff that you dont expect can be the issue.
Is that bcg a ramped or unramped bcg? Kind of hard to tell via your pics.
Ramped= standard fire control group
Non-ramped = you have to use a notched hammer.
Again, just trying to eliminate items.
Edit: your buffer spring could also be too stiff. Is it a standard C spring or a heavier one?
(https://www.opticsplanet.com/guntec-usa-ar-9mm-cal-car-buffer-and-spring-set.html) this is the buffer spring and buffer or at least a product page for it. not sure what you mean by ramped or unramped but ill throw up another pic
so after playing with it if i have it on fire pull the trigger and then rack it hard and fast all the way to the rear it hammer follows, but if i do it slow its fine
edit: if i slowly pull it back and let go of the charging handle while the trigger is pulled (simulating as tho im firing it) it hammer follows but i return it to battery slowly its fine
Unramped on left, ramped on right. The ramp changes where the hammer face impacts the bolt.
I’m looking on my phone but appears you have an unramped (side profile pic would help). If that is the case you need a 9mm notched hammer.
Other option: is the bolt marked PSA Hybrid?
i believe it’s ramped
EDIT: it’s not marked hybrid just G4-9.
Ok, that is still a ramped and should work. Do you have another fire control group or hammer you could try? I really think that is the issue.
