Neck Sizing/Seating Depth

[jschluter]

I apparently don't have enough confusion in my life, so I've started to load CB's in my 45-70 Sharps. I'd like to hear some thoughts on neck sizing depth on the case versus bullet seating depth (either absolute or as a percentage of the driving band length). I want to minimize the depth of the neck sizing for case life yet I want to provide sufficient support for proper bullet alignment. Is this a cut-and-try issue or are there some usable guidelines?

[geargnasher]

Hi J, we're practically neighbors, I live outside Kerrville. I haven't loaded for the 45/70 in a few years, but still load for .45 2.4, smokeless exclusively. I partial-size in a 45/70 die to get the neck tension I need, and full-length size new brass or after a few firings when it starts to get tight in the chamber. Depending on how much difference there is between ideal boolit diameter, loaded cartridge diameter in the boolit area, and chamber size, sometimes you don't have to work the brass much at all. If you wrap your boolits in paper, you don't have to size the cases at all, especially if you use Starline brass and don't anneal it.

Gear

[largom]

I don't load for a Sharps but in all of my rifles I find the maximum over all cartridge length, where the boolit touches the lands. You can then measure the amount of boolit protrusion from the case. You can then neck-size your case for the amount thats inside the neck plus several thousands more. Most handloaders seat their boolits 10 to 30 thousands off of the lands. Your gun will tell you the best seating depth.

Larry

[williamwaco]

I apparently don't have enough confusion in my life, so I've started to load CB's in my 45-70 Sharps. I'd like to hear some thoughts on neck sizing depth on the case versus bullet seating depth (either absolute or as a percentage of the driving band length). I want to minimize the depth of the neck sizing for case life yet I want to provide sufficient support for proper bullet alignment. Is this a cut-and-try issue or are there some usable guidelines?


J,

Based on my personal experience with cast bullets in rifles and handguns, you don't need to worry about case life. At reasonable cast bullet pressures, your cases should last practically forever.

Neck-sizing the 45-70 seems like an inappropriate description to me but I can go with partial sizing. I do that with my .38-55.

You can visualize how much you are sizing your case by marking a black marker line on one side lengthwise on a fired case ( unlubed ) and running it into the resizing die. The black will be marked off where the case is reduced.

I partial size my .38-55 by backing the sizing die out about a fourth inch from the shell holder.

How much to back out your die will depend on your chamber and your bullet sizing diameter.

I would start by backing the die out by four complete turns of the die. That would be 0.28" Load 20 and try them out. If they work OK, back the die out a half turn and try again.

At some point you will decide it is OK, or you will begin to notice tight chambering.



One more thing: Always listen to Geargnasher.


.

[popper]

47-70, straight wall case. Size for neck tension and don't worry about case life. Can't fix mouth cracks, annealing may be tricky.