forming 308 Palma brass to 260 AI

[atl5029]

I am thinking about trying to form some 308 Palma brass to 260 AI and use small magnum primers in order to reap the benefits of the longer brass life of the small primer palma brass.

I imagine that all I would need to do would be to run the 308 Palma brass though my 260 AI sizing die to neck down the brass to .264, load a fire-forming load, fire form, and then trim. I had a few questions though:

1. In sizing down the palma brass, could I use my AI die, or do I need to use a standard 260 Rem die?

2. Can I size from .308 to .264 in one step?

3. Any other steps I am missing?

 

[DocDoc]

Going from .308 sizing to .264 the neck walls will be thicker than normal. You will very likely need to turn the necks to get the clearance you need fo good release of the bullet. Too little clearance and pressures go too high.

 

[atl5029]

Going from .308 sizing to .264 the neck walls will be thicker than normal. You will very likely need to turn the necks to get the clearance you need fo good release of the bullet. Too little clearance and pressures go too high.

Ah yes good point. Do you think I'll need to turn the outside, ream the inside, or both?

 

[atl5029]

Going from .308 sizing to .264 the neck walls will be thicker than normal. You will very likely need to turn the necks to get the clearance you need fo good release of the bullet. Too little clearance and pressures go too high.

Ah yes good point. Do you think I'll need to turn the outside, ream the inside, or both?

 

[DocDoc]

I think the best results are expanding with Sinclair die, then turn the outside of the entire neck.

 

[Jerry M]

Try 7mm-08 as an interim step.

 

[MNbogboy]

Sizing 30-06 cases to 6.5-06 & .25-06 in one pass is simple with full length dies and good lube such as unique....case wall thickness can increase .002 in theory but actually some of the brass is forced backwards to the do-nut area....have also created .260 & .243 cases from .308 in one pass...Depending on your AI's chamber and initial brass thickness you may or may not have to turn necks....Make up a dummy load (bullet only) and check for easy chambering...A snug fit may indicate that neck turning might be required...Use lamp black or sharpie to determine where interference is....

But use the regular 260 die for necking down to prevent case deformation and help maintain concentricity....

Good luck,
Randy