OP, when you say Montana bullets, do you mean Montana Bullet Works, their 10MM, LBT 200GR, WFN-PB?
If so, I shoot this bullet in my Glock 20 OEM barrel at .401" diameter, using Longshot powder to 1161 fps, loaded overall length 1.23". It is reliable and accurate. In my 6" KKM barrel it makes 1300 fps.
Brass expansion in either barrel is minimal. It is a quality bullet, little to no leading, and penetrates very well.
Last edited by mannyspd1; 07/19/19.
