r/AR9 • u/ImpulseRecoil • 1d ago

Buffer spring help

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I have an Aero EPC9 and installed the buffer kit thst came with it. Im missing the buffer spring but I do have the 7.7oz weight. What would be a good buffer spring to get for it? I know the kit says a warning length .308 spring, but would a 5.56 spring work?

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9

u/Blowback9 9mm AR Guru 1d ago

Standard carbine 5.56 spring is all that a 9mm needs. A lighter than carbine (300BO) spring is OK and will help reduce the ROF a little for FRT builds.

XP, .308, Red, etc. springs increase felt recoil, increase bolt bounce, and can cause trigger reset issues.

Details: https://blowback9.wordpress.com/2022/08/18/4-step-guide-to-make-almost-any-ar9-run-100/

2

u/a-lone-gunman 1d ago

What buffer came with it? The early ones were a solid buffer. Aero later changed to the dead blow style and thats what you want. And as Doug said use a standard AR15 carbine spring. Also does it have the old school feed cone or the newer improved feedcone on the barrel, if its the old style get the Macon Armory EPC9 mag catch, it raises the mag up and gives the ammo a better straight shot into the chamber, or get a newer EPC barrel with the better feedcone. You can look at Dougs site Blowback9 and under the Aero Precision section you will see what I am talking about with the mag catch, Doug used some of my pics because he was helping me get it running when they first came out. I have changed mine up a few times since I got it and its now a full time suppressor host with a maxim rdb buffer in it.

2

u/ImpulseRecoil 1d ago

I have the 7.7oz buffer as well as the deadblow buffer.

2

u/a-lone-gunman 1d ago

Ok good, use the deadblow.