Been loading for my .243 Ackley for awhile now, and I've noticed that since the cases were new fireformed, the trim-to length hasn't changed much at all if any. I guess that's because of the nearly straight-sided casings that come from the Ackley design and proper die set-up. I'm reloading the same casings now for the 5th time, and although I check trim length on every one, the length hasn't changed. I'm impressed. Any other Ackley shooters out there have any comments??

I'm on my third reloading with Lapua brass with no trimming yet. Some are starting to get a hard bolt closure though...

You are correct that straight-side, sharp-shouldered cases need little, if any, trimming. The brass doesn't flow much. But rounds like the 300 H&H are just the opposite. Even the 270 Win. stretches pretty badly...

Yep.....The 300 H&H is the prime example of why a belt was needed. Not enough shoulder angle along with a relatively sharp body taper to headspace on properly....In effect, causes brass to flow forward much faster.

In my 22-250 AI, I seeon first firing the original case that it shrinks to fill the void where the shoulders and sides have not blown out. So to start out the case gets shorter. Usually after that I trim them once to make them uniform and never had to trim them again. To be honest I see that as a big plus beyond the additional 100-150 fps I get over standard loadings.

Not crimping also helps, I've been shooting my 223 AI for about three years now and come to think of it I haven't had to trim any of the cases yet.

Jeepkid, Set your die to bump the shoulder a little more. The tight bolt close is not because of the overall cartridge length. If your die is set to bump the shoulder back .001 to .002 you'll see the bolt closing a lot easier. If you don't have a headspace guage just bump the shoulder a little more each time and try to chamber it until it closes nice.

One of may reasons I want to build a 243AI..