Bulge in 4570 reloads

I've been hand loading ammunition for 35 yrs now, and find it real relaxing and my ammo always shoot as good or better than factory. I really like how i can load ammo to a lower velocity and lighter recoil for the off season plinking , especially for my wife and kids, soon now my grandkids (4 yrs old now) mostly use my 45-70's for off season fun , aqquired another to my batter this week a 1998 manufactured ported guide gun , who will be stabled with my 1998 manufactured 1895ss and 2000 manufactured 1895 cowboy.
now to the bullets , my guns shoots lights out with the accurate molds in gas checked 420 and 350 grains. I size them to .459 and resize my brass full length with lee dies , problem is the bullets bulge the cases a little in the resized brass, brass resized to small i guess . how can i resize my brass so its not too small for the bullet , but still got a good crimp to hold the bullets in heavy recoil? i got a factory crimp 45-70 die as well .
Sorry for the winded post
Newfie

Screw the sizing die out (quite a few turns) to only partially resize.
(especially with larger dia cast)

I raise the 45-70 sizing die around .470 from touching shell holder. Die ring is locked at touch and a washer is under it. This allows hand seating my 460 dia bullets in bpcr loads. A special expander cold be made but your still sizing the brass down the same so the bulge will be there.

If the load is shooting "lights out" and everything is working why fix a non problem of a sizing die sizing small and expanding up. ( I have seen 45 acp with .452 dia bullets that looked like a coke bottle)

I’ve got two different sizing dies for my .357mag/max, and one sizes .003” smaller than the other. They both shoot the same and so far brass life is the same. Doesn’t hurt a thing.

Will they still chamber? If so, for myself, I’d call it a non problem. The brass you’re using may be the problem. Starline being the thickest and Remington being thinner. That may reduce the swelling

Rule of thumb w/ Cast (especially when Roll Crimp used for primary retention).

Minimally resize, and minimally flare . . .
Consistent with "some" neck tension, and clean bullet start (dime's width).
- Saves brass
- Saves bullet diameter

Everyone has given excellent advice. Only size the cases enough to have the neck tension to hold the bullet. It will take a bit of trial and error to get it right. Once you do lock the die in that position in order to repeat it next time. Using this method is usually pretty important in 45 Colt also.
Rick

That's common with most straight wall cases---- ones for handguns also. .38/.357, .45ACP, etc.
On the upside, the boolits will never set back in the case under recoil!
As said, if it bothers ya, raise the sizing die a little.

Nobody mentioned the Expander/Belling Die?

Expanding the Case Mouth and Belling it after it is full length sized is a necessary operation. The Sizing Die doesn't do this for you. It makes the case mouth much smaller which then must be expanded and belled to facilitate boolit insertion and proper neck tension. It is a separate operation just like on a pistol cartridge.

After seating the boolit you will need a decent roll crimp to hold the boolit in place. It is best to do this as a separate operation as well so that you can control the crimp more precisely.

Typically you want a 4 die set including a Sizing Die, an Expander/Belling Die, maybe with a hole thru it so you can Charge the Case in the same handling, then a Bullet Seating Die and a separate Crimp Die.

I have used two bullet seating dies in the past with one set up with the seating stem removed or backed out so it would only crimp, in fact the cartridge shown was done with two seating dies set up that way..

Randy

Some time ago (I just searched back 29 pages with no luck),
I believe Waksupi wrote refresher post on how to use
the RCBS Cowboy die set to cure the problem in
the OP. The cowboy die set works for me !

Quote:

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Originally Posted by W.R.Buchanan

Nobody mentioned the Expander/Belling Die?



Randy

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I will mention it. Now:

NOE expander plugs have made my loading results so much better...

This will be long winded but for myself 45-70 brass is not cheap and I hope to make it last as long as possible.
I use the standard RCBS die set. I did try the cowboy die set but other than looks they did the same thing lol.
If you set up the sizer die as recommended it will size down the brass far more than needed thus shorten case life significantly. You do not want to work your brass any more than what is needed. So this will be trial and error. You would back off the sizer die to size the brass say .003-.004 smaller at the case mouth to fit the bullet diameter to have good grip on the bullet. As for boolit size for the Marlin 45-70 .460 is the best size. Some get away with .459.

As for belling the mouth of the case Lee has a universal belling die that is cheap and of course NOE has expander plugs or just use a set of needle nose pliers close them of course and simply put it in the case mouth and give it a couple of turns till you are happy with the bell. It does not take much.

Bullet selection there are many but again try and stay sized at .460. My boolit of choice for what I do Deer and Hog is the Ranch Dog 350 grain.