Designing the 2-diameter paper patch bullet.

[Kurt]

Arnie sent me some of his .40 hard alloyed DDEPP bullet and I shot them into the rest snow bank to see how that hard alloy obturate. I shot them in the .40-65 and the .40-70 both rifles have a standard chamber dimensions. I could not use these bullet in the .40-65 CPA rifle because it has a tight chamber for using the PP bullets only. His bullets won't even fit the fired cases shot from that rifle.
I was impressed the way they survived fired in the standard chamber. The only land cuts where on the expanded base diameter, no marked at all on the bore riding portion. The patched diameter was perfect that kept the bullet aligned perfect in the bore so there was no signs of runout or stripping in the narrow base band giving it full rotation.
Best of all there was no setback, the bullets are just as long fired as before being fired. Unfired they are 1.328" and recovered fired 1.328".
I don't think that hard of an alloy will obturate at or below bore diameter to make full contact in the grooves from what I'm looking at with these, but I might be wrong.........Kurt