Designing the 2-diameter paper patch bullet.

[beltfed]

Kurt,
I recommend you look at the Seth Cole 55W or 55Y for thinner 0.0015" paper for that JIM 395415E bullet.
If you need some to try, I can spare some of each.
Let me know.
Also, indeed, I presume your chamber is a PP chamber with Neck I.D. at or close to bore of 0.3994.
I have a DDEPP drg I provided to Harlan Glover for his 14 twist 40-65. Could send you that drg. Bullet is 1.43-1.44" long.
It is shooting well for him
Mod Elliptical with a 0.19" hemi meplat.
Simple matter to provide an E- PP from that drg. Just leave off the 'patch to groove" base band,
making it into a straight sided slick of appropriate dia to fit your PP chamber.
beltfed/arnie