Cases sizing down my lead.. Why did I bother slugging barrel?

[djryan13]

I am working on 45-70 loads for a Taylor and Co sharps rifle. I have done quite a bit of research including reading the SPG BP primer and Lyman BP handbook but I am grossly confused about something I am seeing. While this example is for black powder, my question is more general as I have now noted this with some smokeless rounds as well.

Details:
Slugged bore to .461 (huge).
I expanded using an RCBS expander plug but even at the highest diameter, when I pull the bullets, the cases had sized them down to .459.
I have since purchased the Track of the Wolf expander plugs in .460, .461, and .462. They were cheap so I did a test.
The .462 gives no neck tension. Obviously.
The .461 gives just a little but doesn't size down the soft lead.
The .460 starts to size lead down a bit.

The books and online say to pick an expander that is .001-.002 SMALLER than bullet diameter. That makes no sense. Why am I casting for a big bore if I only end up sizing the lead down in the case neck?

I am inclined to leave it at .461 and do a minimal (if any) crimp.

What am I missing?

BTW.. This is a great forum. Been haunting it for years (learning a lot) and only recently joined. Figured I would say hello.

[Tatume]

Welcome to the forum.

Since you're loading black powder, and I assume your alloy is soft, you're probably going to find that your 0.459" bullets shoot very well. What condition are you trying to correct?

My personal philosophy is to shoot first and ask questions later. If the load shoots well, shoot it. If not, then dig deeper and try to understand why. I don't slug barrels unless the targets tell me to.

Take care, Tom

[Old Scribe]

Welcome aboard from the State of Jefferson. Like Tatume posted load some and see what works. Don't make a science project out of it .

[44man]

For a Sharps you don't need a lot of tension, just enough so you can extract without losing the boolit.
For some of my over size boolits I don't even size, load as fired.
Use a hand decapper to remove primers. Flare with a tool and just remove the flare if need be, don't bother with a crimp. Sometimes I leave a little flare to center the front.
My Browning needs .460" but I have used to .464". It refuses to shoot under size. Bump up has never worked for me with any gun.

[djryan13]

Thanks guys. I actually really liked the results with the .461 expander but may try .460 only because I want to get enough tension to keep the rounds together through longer term storage. I prefer to load a few hundred ahead and shoot as I please so I can get onto other projects. Not sure that matters.

I guess I am probably over thinking it.

[runfiverun]

your bore is 461 so I'd try for a 462 boolit diameter final diameter that is.
if you stuff a 463 into a 462 ID case your gonna hold everything tight and to the right diameter.
instead of fighting what's happening let it work for you.

one other way around it is to add some toughener to your boolit alloy, that way it will resist the squish of the case.

[montana_charlie]

One thousandth of an inch of neck tension is quite light, and should not size a bullet down.
If your bullet starts out at .461", and is reduced a little when pushed into a .460" mouth, there are two things you can do.

Cast your bullets from a slightly harder alloy ... or anneal the cases to soften the brass (are you using Starline cases?).

Personally, I use no neck tension at all.
I leave the fired case unsized, and thumb seat bullets that are just snug enough that 'lube suction' holds them in the case.

[Wayne Smith]

I did much the same thing with a Trapdoor, thumb seated in unsized brass, but then put a very light crimp on them to hold the boolit in place