WB
I finished a few test rounds last night.
Wednesday, October 29, 2025, 06:54

For the 5.7, I wanted to see how hard it was, all the hype. The loading is straightforward. It's just a little rifle cartridge. The plastic coating on cases seems to be retained and I think well lubrication helps this a bunch. It is said the FL sizing can take a lot of it off. The coating is needed for slick extraction. Guys even have products "clear coat" to re-apply and restore cases, post loading.

The charge is also minuscule and sensitive. A few tenths one way or another is a large "percentage change". I loaded 6.5 grs. of AA#7 with a 40 gr. bullet. IN the bullet box I found an old FA .224-32 loaded round I made from necking a .32 H&R. It holds twice teh powder and I remember I used much slower H110 compared to #7 which is very fast burning for 9mm and such. The FA was running 2150 fps from a 7.5" revolver and the 57 is supposed to be 1600-1800 fps from the 5" semi-auto.

There is some concern pushing the shoulder back far enough to chamber correctly. All you can do it bottom out the sizer. I'll see tomorrow maybe. I can trim the die if it's too close. I want to check for velocity, consistency, and shoulder movement upon firing that will indicate locking character. The guns can begin to open while pressures are high enough to move the shoulder. Yikes! Virtually all 5.7 are some form of delayed blow-back, but pretty high pressure.