For many years, I have been using 444 Marlin brass to form 7X57 and 8X57R cases. Started when friend of mine showed up with his dad's 16X16 over 8X57 Sauer drilling. He had no brass and asked if I could make him some ammo.........
First thing I tried was 303 British. It worked but left quite a bulge around the base because the case head was too small. Cases didn't last too long and sometimes, if the bulge was not oriented properly in the chamber, they would not chamber easily.
Then one day, this was about thirty years ago when my brain was still functioning, the light went on! I necked a 444 case down to 35 in my 358 Win die with the expander ball removed, then full-length sized it in my 8X57 die. One pass with lots of lube and, "Voila!", a perfectly formed case. Didn't even need to be trimmed. Called George and told him to bring his Sauer over, and sure enough, it slipped right in and the action closed without a hitch.
I formed all the empty brass I had, loaded them up with the starting load in my Speer manual for the 8X57, and we headed off to the range. Five shots at 100 yd, and we knew we were in business. To say my friend was pleased is an understatement.
To make 7X57, I just carry on necking down from 8mm to 30 with my 308 Win die, then FL size to 7X57. All standard dies, no special orders needed.
The case head is the correct size, no bulged brass and they last forever at pressures suitable for the old drillings, combination guns and single shots. This brass could be used to form any of the X57R cases.
Ted
First thing I tried was 303 British. It worked but left quite a bulge around the base because the case head was too small. Cases didn't last too long and sometimes, if the bulge was not oriented properly in the chamber, they would not chamber easily.
Then one day, this was about thirty years ago when my brain was still functioning, the light went on! I necked a 444 case down to 35 in my 358 Win die with the expander ball removed, then full-length sized it in my 8X57 die. One pass with lots of lube and, "Voila!", a perfectly formed case. Didn't even need to be trimmed. Called George and told him to bring his Sauer over, and sure enough, it slipped right in and the action closed without a hitch.
I formed all the empty brass I had, loaded them up with the starting load in my Speer manual for the 8X57, and we headed off to the range. Five shots at 100 yd, and we knew we were in business. To say my friend was pleased is an understatement.

To make 7X57, I just carry on necking down from 8mm to 30 with my 308 Win die, then FL size to 7X57. All standard dies, no special orders needed.
The case head is the correct size, no bulged brass and they last forever at pressures suitable for the old drillings, combination guns and single shots. This brass could be used to form any of the X57R cases.
Ted
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