Necking down?????

[vanders]

I'm looking at necking down .308 Lapua cases to 7mm using Redding bushing dies. I've been advised that I should use .309 -.311 bushings for standard 7mm-08 cases, but obviously with necking down from .308 the necks will be thicker. How can I find what size collet to get & how do I know if the sized neck is too tight when projectile is seated?
I don't have a neck trimmer.

 

[Kodiak99317]

To find out if it is too big/tight, seat the bullet you will use in it and measure the loaded case neck size. To find out how big your chamber neck size is, measure a old fired round from your rifle before sizing it.

 

[mikecr]

I think all you can do is try it & measure your results. The bushing sounds right, but it wouldn't surprise me if you end up needing to turn the necks.