Thread: Kimber Montana Ascent 280AI Load Development

Looking at your previous groups they all seem to be more vertical than horizontal but this one at 61.5 has good vertical.....maybe doing a seating change will tighten that up more rather than altering the rifle.

The barrel wasn't well floated so just sorted that. Trimmed the front mount screw as known to touch barrel threads. Also relapped rings as rear was not quite true. Would be nice to bed the recoil lug but not done bedding before so will park that. I'm sure a FDE cerakoted stock would take 0.5" off the groups!

Yes I'll try 61gn see if that has the vertical flyer still - you are right @wsm junkie the 61.5gn group seemed better for that...just getting near max so will play with 61.0gn seating depths.

Interestingly factory new norma brass was often still a firmish bolt close. Stiff to lift the bolt too of course. Even once fired unsized brass could be like this. A strong cam over didn't seem to help so I tried a just touch shell holder die base FL size followed by a run through the body die. The body die just touching the shell holder and a case felt like no work was done but what a world of difference...super easy bolt closure now. @Mooseman may be something for your boy to try...

COAL of 3.330 loads ok but groups were not great. Going to try 3.250 and even 3.200 COAL with 162gn ELDM. This will send pressure up so might back off to 60gn.

I would be inclined to give up with that powder when getting to 120thou jump.
May be a faster burning powder? Rl22 or 23 may be

I had almost the exact same issues getting the 162 to group and changed to the 180 eldm and got .5" groups straight away

kimber 280AI 59g RL26 180eldm 2830fps 22" barrel OAL 3.380

Originally Posted by burtonator

I had almost the exact same issues getting the 162 to group and changed to the 180 eldm and got .5" groups straight away

kimber 280AI 59g RL26 180eldm 2830fps 22" barrel OAL 3.380

Attachment 164674

Deadly combo there.

180 eldm is an awesome pill. Way more consistent killer than the 162 eldm or x

Wow that is good and is a go if no joy. I do want a mag fitting round though.

Originally Posted by Tikka7mm08

Wow that is good and is a go if no joy. I do want a mag fitting round though.

That fits in my mag

I'll do a dummy up at that length and see if it fits the MA.

Trying depth test with 150gn LRABs.





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Barrel will be toast by the time you settle on a load


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3.325 clean barrel. Pulled last shot right.



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outta curiosity was the pulled shot the fastest ?

sounds like you need to load 3 more and shoot it again bud