Any .280 Ackley fans?

[Handsome Rob]

I am really, really struggling to find a good accurate load for this thing. It's a savage action, pillar bedded in a boyd's stock, fully floated, 26", 1:9 magnum profile barrel. Chamber was reamed by Bison Gunworks. I've had several barrels from Bison & they're all been sub-moa shooters, so I'm doubtful that it's a barrel issue.

I've only tried the heavier end of the bullet spectrum so far (Hornady 162 eld-x, Berger 168vld & Hornady 154 sst) with imr7828 & Retumbo, keeping velocity to around the 2850-2900 range. The best 3 shot group I've managed is 1", but shots 4 & 5 open the group up to nearer 2" (timed 3 minutes between shots)

I'm really undecided whether to try lighter, say, 139gn pills at hopefully 3200+ (which I know is doable) because I've already got a 6.5 Swede that pretty much fills the 140gn bullet niche, although I don't get the speed I could with the .280

I built this with longer range, western hunts in mind where shots 'could' range out to 600+ yds & I was hoping to be able to go heavier on bullet weight to take advantage of the higher B.C.s offered over a .30 & carry more weight & energy than my 6.5 for large mule deer & elk sized critters.

I'm thinking I need to try different powders. I know rl22 is the go-to for .280, but it's too temperature sensitive for my needs. I'm told that IMR/H4831sc could work.

So, in y'all's opinions; should I go light & super fast, or try to find an accurate, heavier option?

Anyone wanna share recipes, cos I'm tearing my hair out here!

[gregintenn]

I only have standard 280s, but IMR4350 and about anything 140 grain seems to be laserbeam accurate.

[deadeye111]

I had a Remington 700 SS with 26" bbl but was only .280. I got good results like Gregintenn with IMR 4350 but IMR 4831 gave around 3100 fps with good accuracy with Sierra Pro Hunter bullets.  The latter was what I used on deer and they didn't run usually. I think the 5th Edition Sierra manual has info on .280 AI. If not call Sierra "Bulletsmiths"

[Climber]

I have a Kimber 280AI and I struggled for a while to try something that worked.  I finally did a full bedding with trigger work and found a 140gr load that is lights out.  I have not tried anything in the 160gr range but have been itching to try to work something up.

[Sunfish]

Rob,

   When you consider choosing different components remember the 280AI is a 7mm-06 with a 40 degree shoulder angle. That said try a full case of Ramshot Big Game with a Bonded 150 or 160. The extra capacity that the shoulder angle gives may be more trouble to do than the performance you achieve but that's another story. This will end up trading velocity for consistent downrange energy. Let us know how this shakes out. 

Edited November 6, 2016 by Sunfish