Muleyfanatic
Active member
I finally got to play around with 280ai this weekend. I free floated the barrel, lightened trigger to 2.5 lbs, and set stock stock screws to 50 in lbs tightening the back screw first.
I loaded up 140 accubonds to sammi specs since that is what fits in magazine box without any room to spare this puts the bullet about .300" off the rifling (not misstyped it has that much free bore). I used H4831sc and federal 210 primers. 60 grains grouped good, 60.5 grouped the best, 61 started to open and got worse as I worked up to 62 grains. The group at 60.5 was .380" so I decided to stick with it. On Sunday I went back to the range and chronographed the load since the barrel was now broke in. The load ended up giving me 2882 fps measured with a oehler an es of 22 fps. I am a little disappointed with the velocity but the accuracy is unbelievable staying under .400" consistantly. I guess I got a slow barrel or something because I see a lot of people posting about 3200 fps out of the 24" barrels. I know I get to 3100fps but accuracy suffers to much for me. I topped the rifle with a Boone and Crockett 4.5-14 that I got off predator optics. This bullet weight and velocity matches with in an inch out to 500 yards so figure it will be good medicine on deer, black bear, and back up elk rifle. Will still carry the custom rifle most of the time but am very impressed by the kimber Montana's accuracy for a light weight factory rifle.
I loaded up 140 accubonds to sammi specs since that is what fits in magazine box without any room to spare this puts the bullet about .300" off the rifling (not misstyped it has that much free bore). I used H4831sc and federal 210 primers. 60 grains grouped good, 60.5 grouped the best, 61 started to open and got worse as I worked up to 62 grains. The group at 60.5 was .380" so I decided to stick with it. On Sunday I went back to the range and chronographed the load since the barrel was now broke in. The load ended up giving me 2882 fps measured with a oehler an es of 22 fps. I am a little disappointed with the velocity but the accuracy is unbelievable staying under .400" consistantly. I guess I got a slow barrel or something because I see a lot of people posting about 3200 fps out of the 24" barrels. I know I get to 3100fps but accuracy suffers to much for me. I topped the rifle with a Boone and Crockett 4.5-14 that I got off predator optics. This bullet weight and velocity matches with in an inch out to 500 yards so figure it will be good medicine on deer, black bear, and back up elk rifle. Will still carry the custom rifle most of the time but am very impressed by the kimber Montana's accuracy for a light weight factory rifle.
Last edited: