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7X57mm Mauser Ackley Improved
ochoco
Member Posts: 216 ✭
Anyone out there worked up a load they would like to share?
Comments
If you haven't already worked with the Ackley cases you will find you'll hit top pressures and go over pretty quickly when you do. Look carefully at every level of your ladder to see pressure signs. Often in regular cases we look for flattening primers. These {Ackley's} don't do it that much until you're too high. As soon as you see a flattened primer - back off.
One other way I've been able to gauge pressure is to look at the side of the case. Normal firing leaves the side looking mostly dark brass. If the pressure/heat is high you can sometimes see the body of the brass turn lighter. This comes from it nearly coming to the melting point. The line where this turns is the indicator. If it's way down on your web area it's too hot. If it's right down to the top of your web area it's just about right. It's very slight and not always easy to see. But, if you're too hot you'll see it. Usually before you spot loose primers.
If you don't already know how to load a ladder, pm JustC or myself and we could help.
Also, last edit:
One of the biggest reasons people who compete, shoot the Ackley cases isn't to get more speed. It's to save case life. The case grips the chamber walls better than the parent case. While you can get more slower powder in the case to give you better speed, the dynamics of how the case stays in place better are what minimalizes movement and therefore case stretch and thus longevity of cases. Load these up to where you find accuracy nodes in your rifle then leave it there. Don't go chasing the velocity vixen/fairy and ruin cases and barrels. Maybe even gun or face.
I use a chrono when working with any of my Ackley chamberings, it is almost a MUST. I got 3208fps from a 6.5-06AI in a 26" barrel running a 140gr a-max. Needless to say, even though pressure signs were not present, the chrono clued me in to the error of my ways, but not before the primer pockets were toasted[V]
yep, sandwarrier is spot on. Ackley cases do not show traditional pressure signs until you are wayyyyy high. The straight case taper, and 40* shoulder keep pressure signs from appearing readily, as they have a very positive headspace due to the shoulder and chamber meeting so solidly.
I use a chrono when working with any of my Ackley chamberings, it is almost a MUST. I got 3208fps from a 6.5-06AI in a 26" barrel running a 140gr a-max. Needless to say, even though pressure signs were not present, the chrono clued me in to the error of my ways, but not before the primer pockets were toasted[V]
...me too[B)] My favorite .257 AI of all things.[8D][:0][:D]