ive got a colt factory upper a1 style with a 10.25 barrel  and was wonderin what the twist was on those barrels  it was made in 97  chrome lined, chrome chamber

also what bullet weights are you guys useing?

Typical COLT factory barrel, along with most of the other aftermarket vendors is 1x10.

My 9mm barrel is cut from a stainless blank,  8.5" long, and 1x10.  I shoot what ever through it.

Common pistol barrel is 1x16, and we shooting 147's out of those, and subguns/carbines be 1x10, so 147gr-158gr be fine.    Currently with having a subgun, to hold costs down of 9mm to feed the thing,  I been sticking to 115gr bullets, and loading moderately.