Neck tension

Here's an alternate way to do this. Don't use an expander each time you reload. For my .30 cal. rounds, after being fire-formed, I have a Sinclair neck turning “spud” that I use to “over-expand” the case mouth. Then using Redding's instructions, I select a neck sizing bushing that is used to “squish down” or reduce the OD of the case mouth. As an example, if the CB is 0.310” and the case necks measure 0.013"; you double that, add the CB diameter and then subtract 0.002” to 0.004” to arrive at the bushing size to use. The calculated OD would be 0.336” and deducting 0.003” would tell us to use a 0.033” Redding bushing. Then after each firing (the case mouth has already expanded from firing) you just run the neck through the same bushing.

Using the long tapered Lyman case mouth inside deburring tool lets you avoid having to use an M-die to allow a bullet to be seated without damaging the bullet..

The key is to experiment to find which size bushing gives the best result because it seems as if each gun likes a specific amount of “neck tension". But now you are no longer pulling an expander through the case mouth, stretching or lengthening the case. And how often is the factory die set-up with the “best” expander for your situation?

For my 74 Sharps in .40-65 the case is reloaded after firing “as is". Prime it, drop in the black powder, insert the wad, compress, drop the bullet in (it comes to rest on top of the wad) and use a Lyman taper crimp die to just lightly hold the bullet in place so it doesn't come out during transit or handling. That's probably a case of 0 neck tension.

FWIW

Tom

Tom