Hello Brent,
I did a chamber cast and best as I can measure, I get about a .460" dia groove. A Paper patch bullet from the rifle's mold is .450" dia so a couple of wraps of a thick paper should do it.
However, I'm not using the paper patch bullets. I don't I have have enough time before the hunt to properly learn the technique and test loads. Weather is turning bad very quickly.
After trial-and-error testing of several different powder levels and a few different bullet weights, I've settled on using a 293g 2-groove 45 cal express bullet from a mold in my collection. I'm loading it with 42.0g IMR 4198 and a foam backer rod as a case filler.
A 100 yard 10-shot group this morning resulted in a group that measured 3" wide by 4" high. I think I might have done better were it not for the bad weather. A cold 34 degree temperature with spitting snow and 10 - 20 mph wind gusts coming from left to right.
Chronographed velocities for the first 5 shots were: 1711, 1694, 1689, 1725, 1698 = 1703 ave.
I'm thinking that's good enough - I'm ready for the hunt.
