My first .280 , a Ruger 77, 22" doted on IMR 4831 55gr and 139 Hornady. I never chronographed it, but it was most likely 2900 or so. I had a Mod 700 Mountain rifle ( 22") reamed out to the 280 AI ( early 90s) and with R22, I still only got 2950 with the 150NBT. I tried R26 in a 22" .280 a couple years ago, and the rifle didn't shoot it well, but speed was up there! I had a 22" .270 that loved the stuff...you pays your money and you takes your chances, ha. I did get 3000fps with R22 out of a 22 inch .270/140 for my SILs rifle. So, if you work up with R22 in hot weather, you will be OK. In that 280 AI I had, I worked up that 61gr load of R22/150 here in Utah around 40 deg. I went to Texas and shot a Corsican Ram and the bolt stuck, had to really hammer it hard with my hand. When an Ackley does that...wow! ha Good luck to you though.
Last edited by Jim_Knight; 11/16/19.
