Will also comment that the standard .280 handloaded to .270-type pressures gets muzzle velocities very close to the .280 Ackley Improved, because the "improving" doesn't really gain all that much powder room.
John:
Is there a rule of thumb that you use to determine how/when you've loaded to .270-type pressure?
Thanks
Not John but you work up a load in your rifle that gives you the same velocity that you would expect with that powder and bullet weight in a 270.
For examle,if you are using 140 grain ballistic tips and IMR 4350,you can work up to the same velocity levels that one would expect in a 270 or to within 50-100 fps of the velocity that one would expect in a 280AI. Remember to keep barrel length in mind,don't try to get your 22 inch 280 to equal the velocity of a 26 inch 270 or 280AI.
Start with published 280 starting loads and work up in one grain increments watching carefully for sighs of excess pressure. Stop when you reach the target velocity unless you see pressure signs before you get there.
As a rule of thumb,you can get within a couple of grains of the published maximums for the 280 Ackley without issue.
