Hi all, I'm getting ready to turn my Pac-Nor 475 blanks for my 470 NE double project. What would be the minimum safe diameter at the muzzle that I could go with?

I looked at one of the 45-70 barrel inserts today and it was .6" at the muzzle, so I should have pleant of room to save weight.

I asked Pac Nor their opinion on min. barrel thickness and they had some guideline to go by. I do not remember it any more.

I just heard back from Pac-Nor and they said they liked to see atleast .125" per side.

Lar45,

The absolute minimum by the old rule of thumb was 0.20 plus bullet diameter, but most present day barrel makers prefer 0.25 as Pac-Nor told you. That being said, I had in my possesion a 450 3 1/4 Nitro for a short time that was only .605 at the muzzle on one barrel, and .595 on the other (8 pounds and 2 ounces total weight). Yes, it did have a bit of recoil .

Jim

I think I'll turn one at .250" and weigh it. I'm shooting for around 9.5-10.5# finished weight. The .9" unturned blanks are about 4# each.

A 470NE is a good low pressure round and your barrel pressure should be quite low at 22-24 inches. I've gone to .100 with no problems with much much more potent rounds. I would not go below that!-Rob

Rob, is that .1 total or .1 per side???
just checking.
TIA