Might be a slight bit too quick but with 140 grains to 160 - it would be ideal - the original 6x55's were built around 156 grain round nose bullets with long bearing surfaces launched at around 2400fps, and their twist was somewhere around 7.5 - this barrel would be ideal for a modern 250 yard, 6x55 mountain rifle - light-weight yet able to shoot 140's 2900 fps at deer/goats, and sheep and 160's 2700fps at elk and moose. If I didn't already have the same, I would be all over this. Guys, you would have a long wait trying to get a blank like this delivered right now.