The 90 grain bergers are for a 1 in 7 or faster. Have you tested them in the 8 twist? I shoot them in my 22-250. Barrel is 30 inches and I am throated 100 thousands more. This gun is so fun and extremely accurate. I shoot it with hodgdons 4895 at 3000 fps. I could go a little faster but accuracy was fantastic and pressures were good. You will enjoy shooting the heavier bullets. My gun shoots around 2.5 to 3 inch groups at 800 plus yards. My wife shot a 4 point mule deer buck at just under 600 yards this last fall. Very impressive combo in my oppinion and I am glad I made the decision to try the heavy bullets in a 250.
I'm using 31 grains H4895 with federal match 215 primers. Producing 3005 fps.at the muzzle. I tried H1000 and 4831 with outstanding accuracy but about 150 fps less. I wanted to be at least to 3000 fps. Hope this helps. Might load slightly less like I did and work up to avoid any over pressures in your gun. Pressures are good in my rifle. Using a savage 12 action.
I have a lot of shot data on this rifle with different powders and velocity spreads. If your interested just pm me and I can get you what I have for data since there was nothing to go by and I had to start from scratch. I ran 3 or 4 different powders and worked up and kept track of all the info.
I have not shot any coyotes yet work has had me very busy. I will let you guys know as soon as I get an opportunity to get out and shoot some votes. I'm hoping to get out next weekend but work may change my plans.
It would help to stabilize them, but what I've been told by Kirby Allen is that you have to worry about the bullet coming apart and throat life is short for the A.I. version. He said I would be better off running the bullet at a velocity in the 2800-2900fps range in a standard 22-250 case. As I don't have a barrel yet, I can't give any specifics. He also suggested staying with a 1:8 twist.
the cost of switching to the AI was not worth it to me with dies and so forth. the speed in my oppinion is not that much more to really convince me also to go with the AI version. I can push them at over 3100 fps. if i wanted to with the regular 250 but it is extremely hot load for me so i backed them off. I am happy with the performance I am getting. You will be happy with the performance of that round I am sure of that.