Paul wrote:I've just got some 52gr 0.224 Rexem projectiles to load for my 22-250.
Looking at the ADI manual, there are two 52 gr projectiles listed for loading data : 52gr HDY A-Max and 52gr. Sierra HPBT. My query is which one to follow for load starting data etc, as there is a massive pressure difference between the two for a similar load of 2208 once you get above the starting loads. i.e
HDY A- Max 32gr 2208 45,500 CUP,
36gr 50,000 CUP
SIE HPBT 32 gr 2208 45,800 CUP,
36gr 64,100 CUP
This seems ie a really big difference at the higher powder loads for comparable velocities. Im mindful the high pressures. ANy thoughts on firstly which one is closer to the Rexem, and thoughts on the pressure difference?
Which data should I go with, given the differences in pressure?
Thanks in advance.
Paul
Don't get caught up in the minutia, all load data are just a general guide so you have an idea of where to operate. Data for any jacketed 50-55gn bullet will be fine, cast and monolithic copper/brass bullets will have some differences in data, but not a lot. Much of ADI's data comes from computer modelling, not real-world testing so don't regard it as gospel.
When choosing powder look for one that has compressed maximum loads (good case-fill), while making good velocity at lower pressures than other choices.
Start at 32gn as suggested and, if you need more velocity for some reason, work up keeping an eye on any signs of pressure, primarily if the bolt gets harder to open that's a good time to back off. The extra pressure is working your brass harder than you want.
Primers are not an accurate indicator of pressures, at least not until you have lots of experience with that type of primer in that cartridge.