by crbutler on Mon Sep 23, 2019 12:29 pm
Most 9mm (I am assuming 9x19, and not some of the more esoteric hunting rounds) AR style rifles are straight blowback operated. Minimum loads are not your friends. Competition handgun loads that minimize felt recoil are likely to be iffy as far as reliably working the action.
I would use a slower powder (like AA#7) in a rifle load. The recoil is relatively minimal anyhow. A middle of the road load and adjust up or down based on accuracy and reliability.
All of the bullet weights you mention will work fine.
As these are not gas operated, lead or copper fouling is an issue only when accuracy suffers. I avoid cast bullets in long arms like this as they do tend to require more cleaning in the chamber area. FMJ are fine, no need for encapsulated or JHP unless you have a specific need for them, and flat nosed bullets (cast or JHP) can be tricky to feed in some guns.
Once you start loading for certain performance parameters you might want to go with heavier bullets and fast powders for subsonics or hollow points for small game/defensive use.
I would put a good taper crimp on them as they do sometimes take a beating while feeding, and COAL changes are an issue in a case with as little volume as 9x19...