Originally Posted by cross
I've read in various places that expander balls/mandrels on standard full length sizing dies can tweek the case mouths and cause a decrease in accuracy.
I would like to get a set of bushing type dies but don't know how to figure out what size of bushing I need. I'm interested in the Forster Bushing Bump Sizing Dies for my 7mm Rem and the Forster website gives dimensions of the bushings that come with their kit as (.308, .306, .304).
What do I need to do to determine the size of bushing die that I need?
Does anyone here recommend the Forster Bushing bump dies or should I be looking at the Lee Collet dies?
Will the Lee Collet dies give you any shoulder bump and if not, do you recommend hunting with cases that have only been neck sized?
Most of the time with a magazine gun you will need .002-.004crimp to hold the bullet.
So start with a loaded round and see what it measures. Lets say a 308 caliber of some type and it measures .339.
You will get a .001 springback in the neck after you size, so you have to plan for that also.
So in this case, .339-.001= .338-.002=.336 bushing or .338-.003= .335, giving you a .335 neck bushing.
I would go .335 and .336 to start and if the bullet slips, go with a .334
No you understand that they the Forester will not FL size, so plan on using a Redding body die at least every 3 shots or so.