7mmWSM neck diameter
- Thread starter LongDraw
- Start date
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
If you are feeding from the mag, you will need much more neck tension. 4 to 5 thou is usual.
You also have to account for brass spring back which can vary from 1 to 2ish thou. The only way to know for sure is to measure before and after sizing.
So in the scenerio above, you need a 0.309" bushing if you have 14thou thick neck and want 2 thou neck tension and assume 1 thou spring back.
Thicker necks - bigger bushing. Thinner necks - smaller bushing.
More neck tension - smaller bushing, etc, etc.
With bushing dies, I find best success is achieved with neck turned brass. Just clean up at least 70% of the circumferance and try to keep it at least 12 thou thick or you will likely get neck splits. I prefer 14 thou necks after turning but 15 thou is just fine too.
I rarely jam my bullets into the lands, prefering to let a higher neck tension do the same thing. Saves having a bullet pull out, dumping powder into my action, if I need to extract the cartridge.
Jerry
You also have to account for brass spring back which can vary from 1 to 2ish thou. The only way to know for sure is to measure before and after sizing.
So in the scenerio above, you need a 0.309" bushing if you have 14thou thick neck and want 2 thou neck tension and assume 1 thou spring back.
Thicker necks - bigger bushing. Thinner necks - smaller bushing.
More neck tension - smaller bushing, etc, etc.
With bushing dies, I find best success is achieved with neck turned brass. Just clean up at least 70% of the circumferance and try to keep it at least 12 thou thick or you will likely get neck splits. I prefer 14 thou necks after turning but 15 thou is just fine too.
I rarely jam my bullets into the lands, prefering to let a higher neck tension do the same thing. Saves having a bullet pull out, dumping powder into my action, if I need to extract the cartridge.
Jerry
