Hi All,
I have a 7mm-08 and a .243. Since purchasing brass for both; I've been given some .308 once-fired and previously-fired 7mm-08 brass. I expect I'll be given more .308 brass at occasional intervals in the future. I'm interested in resizing some of them down to .243. I'm thinking -
1. Resize to 7mm-08.
2. Inside neck ream with a 7mm reamer.
3. Resize to .243.
4. Inside neck ream with a .243 reamer.
Is the above a safe, doable way to do this? I'd have to invest in a RCBS case neck turner and reamer pilots.
Thanks,
Mark
My successful .308 to .243 conversion process is simpler and works fine.
1.Resize to .308.
2. Resize to .243.
3. Load, then fireform.
Neck ream
only if a loaded cartridge measures too tight in your gun chamber's neck. If it does then ream inside the neck after it's resized (using a sizer without an expander) to .243.
DON'T REAM TWICE as per your steps! Too thin necks will result. Neck may then split first or second reload.
BTW Forster makes reamers sized to ream .243 brass before sizing, or after sizing. Don't know what RCBS makes.
Consider the following: Using a die with an expander ball, when the case is sized (expander ball is in the case), the extra neck wall thickness decreases the inside neck diameter. Then when you pull the die out, the expander sizes the inside of the neck to the expander diameter. Now the outside diameter of the neck gets pushed out. If it's too big, you might have feeding problems, but most chambers are big enough to handle it. No inside reamer is called for here. You could use an outside reamer, but the next paragraph is a better, easier way to go, IMO.
Using a die without an expander, the extra material is left inside the neck...therefore a reamer would be needed to ream inside neck diameter to the correct size to give perfect neck tension. The question is will the Forster or RCBS reamer be that perfect diameter? That's what you have to investigate.
Outside neck reamers are typically made for another purpose. Benchresters use them to make the neck thickness concentric (the same thickness) all around the case, so that bullet release is even all the way around. Not something most of us need, and may be outright dangerous to do in gas semiautos (like a Remington 25 or Dpms chambered for .243), where thin necks (especially at the shoulder) translate to failed brass. If you choose to use one on this brass be careful that you don't cut into the shoulder to much...easy to do with the shorter than factory necks you will experience.