Loaded Ohaus 45-405 bullets, 434.5 +/-.5 grains, Darr lubed, 21.5 grains SR4759, Dacron wad, WLP primers, breech seated, 100 yards, five shot groups, C. Sharps 45/70 Model 1875, 30X STS, Muzzle Clamp/Anti-Cant device. A set of ullets had the bases filed at a 45 degree angle for about half the thickness of the base band. Shot 3/2/05 to see the effect of damaged bases. Windy enough to blow empty plastic ammo boxes off the bench, 70 degrees, bright sun, plenty of mirage. Alternating perfect and damaged bases.
Group sizes:
Perfect bases: 2.1", 4.3", 2.05", 3" Avg. = 2.86"
Damaged bases: 3.35", 2.675", 3.95", 2.9" Avg. 3.269"
I thought there might be lead in the barrel, couldn't find any. I read through the notebook on this rifle last night. Many 10 shot 200 yard groups under 4", many 100 yard 5-shot groups under 2", some under 1", one measured .693"-all with this load. I've used the Wolf No-Grease-Groove bullet almost exclusively in this rifle since 1993, mold is now lent to Mustafa Curtess for testing. I don't know why I'm shooting such big groups in this damaged bullet testing-but here it is.
Maybe these damaged bases caused the larger groups.
joe b.

You might find a copy of Dr. Mann's book 'The Bullet's Flight", published around 1905, very interesting.
He did many tests, including one similar to yours with damaged bullet bases. His results were similar to yours.

Loaded Ohaus 45-405 bullets, 434.5 +/-.5 grains, Darr lubed, 21.5 grains SR4759, Dacron wad, WLP primers, breech seated, 100 yards, five shot groups, C. Sharps 45/70 Model 1875, 30X STS, Muzzle Clamp/Anti-Cant device. A set of ullets had the bases filed at a 45 degree angle for about half the thickness of the base band. Shot 3/2/05 to see the effect of damaged bases. Windy enough to blow empty plastic ammo boxes off the bench, 70 degrees, bright sun, plenty of mirage. Alternating perfect and damaged bases.
Group sizes:
Perfect bases: 2.1", 4.3", 2.05", 3" Avg. = 2.86"
Damaged bases: 3.35", 2.675", 3.95", 2.9" Avg. 3.269"
I thought there might be lead in the barrel, couldn't find any. I read through the notebook on this rifle last night. Many 10 shot 200 yard groups under 4", many 100 yard 5-shot groups under 2", some under 1", one measured .693"-all with this load. I've used the Wolf No-Grease-Groove bullet almost exclusively in this rifle since 1993, mold is now lent to Mustafa Curtess for testing. I don't know why I'm shooting such big groups in this damaged bullet testing-but here it is.
Maybe these damaged bases caused the larger groups.
joe b.

Two more tests seem in order:
Cant the bases but mark the bullet nose to the low point.
Shoot some groups with the bases oriented to the same place in the chamber each time...and groups with them spread arround the clock.

Two more tests seem in order:
Cant the bases but mark the bullet nose to the low point.
Shoot some groups with the bases oriented to the same place in the chamber each time...and groups with them spread arround the clock.

I think you're right. Let us know how the testing comes out.
joe b.