.280 rem to 257 rob ai fail

[zymguy]

Messing around with some 280 brass. Put it through the redding 7x57 form trim die then redding 257 rob ai using wax . Couldn't quite get there. In the back is 7x57 run through trim form die then full length size . I loaded 6 of those with minimum win 760 charge for hornady 117

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[zymguy]

This one I think I moved the 7x57 form die way up

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[BK7saum]

Did you anneal before forming? I get that when I anneal. Sometimes it is better to form before annealing

[376Steyr]

Maybe add a backed-off 6.5 Creedmoor die after the 7x57 to get the shoulder angle and neck diameter closer to the 257 AI?

[stubshaft]

I use 7X57 brass to form my 257 AI brass, remember to anneal AFTER sizing down and BEFORE necking up.

[pworley1]

I think you just need to trim your brass when you use the 7x57 trim die. I start out with 30 06 to make mine, but all I do is run them through the 7x57 form die and cut them with a fine toothed saw then file and chamfer. Next I run through the 257 size die with the stem removed. This is when I anneal and finish by running them through the 257 complete size die.

[racepres]

I think you just need to trim your brass when you use the 7x57 trim die. I start out with 30 06 to make mine, but all I do is run them through the 7x57 form die and cut them with a fine toothed saw then file and chamfer. Next I run through the 257 size die with the stem removed. This is when I anneal and finish by running them through the 257 complete size die.

^^ My Method..270 or '06 brass.. tho I shorten with a Tubing cutter! If I was gonna go to the Bob, From 7x57, I would intermediate with 270 WSM backed off
I guess if I encountered neck collapse like that, I would Begin with stem removed on 8x57 to push shoulder back!! BTDT