I have not owned a 280AI but have had a substantial number of 280's and 7 Rem Mags.,and loaded for the 7x57 in 3-4 rifles enough to get a handle on what it will do compared to the others.
Using 140 gr bullets in each this is where I landed,across the board with each and using mostly 22" barrels in the 7x57 and 280,and 24" in the 7 Rem Mag:
-7x57,2800-2850.
-280, 3000-3050
-7 Rem Mag, 3200-3250.
Caveats: I think the 7 Rem Mag is best suited to bullets 150 gr to 175 gr,and with these it's going to show a velocity advantage over the smaller cartridges. I have run 140's as high as 3300 from the cartridge with no ill effect,but stoop at the 3200-3250 level because there is not much to be gained pushing harder.
In load development with the 280,I have pushed the 140's over 3100 with no ill effects,but found case life better under 3100 fps.
I have not owned the 280AI,and with the above numbers in mind maybe some can see why...yes with a 26" barrel and warm loads it will get close to a 7 Rem Mag but if you give them both the same barrel length and load to the same pressures the 7 Rem Mag will get the same velocities easily.
Someone will come along and talk about SAAMI pressure limits at 65,000 psi for the 280AI and well below that with the 7 Rem Mag,but a look at the Nosler manual shows that even given that the 7 Rem Mag still gets more velocity and the 280 AI is shown with a 26" barrel while the 7 Rem Mag has a 24". I think we have to assume that Nosler is loading both to SAAMI spec.
Another factor to consider is that manual data only sometimes matches what we get in our rifles,and the average hand loader has no idea if he is operating at SAAMI spec or not. So those giddy velocity figures of a substantially smaller case equalling a larger case for velocity are frequently pie in the sky. For this reason I like to rely on a larger case if I want to be certain of reaching a given velocity level.
To my mind the 280AI sits, in case capacity and velocity, right between the 280 and the 7 Rem Mag, but that is a pretty thin niche to fill. It will also give more velocity by a good margin over the smaller 7mm's like the 7x57 and the 7/08 with the same bullets.
In terms of trajectories there seems to be about a 4-5" difference at 500 yards between a 140 gr 7mm AB started at 3000 fps and working up to 3200 fps.....not really a huge spread since that sort of difference could be lost in group size and normal shot disbursement,depending on rifle, load,and shooter
If I were looking at a 280AI it would be a choice based more on the rifle than any advantage of the cartridge. I can live with anything that gives 3150 with a 140 gr bullet,or 2900 fps + with a 160 but since I get those numbers without breaking a sweat with the 7 Rem Mag,I have no need for a 280AI.
BUT....something like a Kimber Montana in 280 AI is pretty unique in a lightweight rifle and if it had existed 30 years ago I may not have gone to all the trouble I did building lighter weight 7 Rem Mags. In a light rifle that is a tough combo to beat.I would like it as well in 280 Remington.
I don't think any of them will kill stuff ay deader than a 7x57 but the velocity differences are there if you want them.
Last edited by BobinNH; 11/27/14.
