Neck sizing for 45-70 PP BP cartridge: question.

[HWooldridge]

The BACO 9lb mikes at .002 and they state it will add .006-.007: in my case it ads .006. That sounds counterintuitive since 4 layers of .002 would be .008, but that’s what it gives.

It’s my intention to acquire 45-90 brass and trim it so that it fills the chamber as well.

Some types of paper tends to shrink so that can be why the final wrap is slightly under the calculated size. Some paper also seems to have a "grain" where it shrinks more in one direction on the sheet.

I don't have my Sharps anymore but I shot PP out of it for a number of years using BP and never sized the cases at all; just washed them and used a long pin to knock out the old primer. The bullet would thumb-seat in the case and never needed any extra work. That rifle did have a glass smooth chamber and always easily ejected spent shells.

[Noah Zark]

Some types of paper tends to shrink so that can be why the final wrap is slightly under the calculated size. Some paper also seems to have a "grain" where it shrinks more in one direction on the sheet . . .

That "grain" of which you speak is referred to "machine direction fiber orientation". In most cases, one can simply determine machine direction vs cross machine direction by tearing the piece of paper. If the paper tears easily and in a straight line, that's the machine direction. If the paper tends to tear to the side, not in a straight line, that's the cross-machine direction. Paper tends not to "shrink" in the machine direction as much as it does in the cross-machine direction.

That said, with modern paper machines having "twin wire formers" the sheet they make tends to be less differential MD vs CMD. In other words, the CMD fiber orientation is almost the same as MD fiber orientation and the sheet will tear more or less the same in both directions. That kind of sheet will "shrink" uniformly in both directions, so one doesn't need to worry so much about it. Modern copy and printer papers are made on very large, wide, and fast paper machines using twin wire formers and produce a sheet with significantly uniform fiber orientation (tears both directions more of less the same way). Writing and stationery papers, particularly those with cotton or rag fiber content, are produced and older, slower single-wire Fourdrinier-type paper machines and their sheets will exhibit significant differences in MD vs CMD fiber orientation, tear, and shrinkage.

Noah

[HWooldridge]

That "grain" of which you speak is referred to "machine direction fiber orientation". In most cases, one can simply determine machine direction vs cross machine direction by tearing the piece of paper. If the paper tears easily and in a straight line, that's the machine direction. If the paper tends to tear to the side, not in a straight line, that's the cross-machine direction. Paper tends not to "shrink" in the machine direction as much as it does in the cross-machine direction.

That said, with modern paper machines having "twin wire formers" the sheet they make tends to be less differential MD vs CMD. In other words, the CMD fiber orientation is almost the same as MD fiber orientation and the sheet will tear more or less the same in both directions. That kind of sheet will "shrink" uniformly in both directions, so one doesn't need to worry so much about it.

Noah

Thanks for the info. I bought a box of paper about 30 years ago and was still working off of it when I sold my Sharps. I now have a rolling block in 45-70 and may wind up shooting PP again, but this rifle has a rough chamber and I haven't spent much time with it. Greasers work well enough in the short term for anything I want to poke holes in.

[ascast]

piwo - good read here, I am way outta my league here but thought it might be useful to you to mention that maybe neck sizing can be done with 45 ACP, or 45 Colt etc. dies, maybe 43 Mauser or 44-77 Sharps 43 Reformondo, NOT 43 SPANISH. I like "fixed" ammo with zero readout before they go in the chamber; certainly for hunting.
I saw a guy tump a whole box of 45-70 once at a match. Bullets came out all over. He had diff loads for diff ranges, including diff bullets, big mess-watsed day for him.
just thought I should mention this..
good luck

[piwo]

HWooldridge, Noah Zark,
Interesting information on the shrinking characteristics of paper. I will incorporate that review step w every batch or paper I try.

[Kenny Wasserburger]

HWooldridge, Noah Zark,
Interesting information on the shrinking characteristics of paper. I will incorporate that review step w every batch or paper I try.

Btw your book shipped yesterday.

Kenny Wasserburger.

[piwo]

Btw your book shipped yesterday.

Kenny Wasserburger.

Can’t wait!
Thanks

[Gobeyond]

Well you need 45-70 dies to size the case with its .458 inside neck, or 45-70 neck sizing dies. But I don’t, I just leave them fire formed to my chamber. Flair the case mouth a little after firing so the bullet can be seated by thumb. Then crimp a little in sizing die to flatten it again. I’m sizing my noses a bit for bore rider noses. Helps stabilize long bullets. I use hardball to get a good grip on rifling.

Rcbs has neck sizing dies. When I put a little crimp on with the FL die should be all you need. But be careful. That’s way less than the bullet width, even with neck sizing. They won’t be very durable until you get them in the chamber.