A few more photos that wouldn't fit in my last post ...

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Reverend Al wrote on Aug 26^th, 2016 at 4:30pm:


That's a Good Idea! I just wasted 50 primmers that I took out of some .30-40 Krag Brass......

Terry

Might try a block in place of the shell holder before shortening the die.
Had to do it on a 38-50. Tough to resize the base of a cartridge. 
Most factory cartridges have a straight section near the base. Reamers are usually a straight taper and can be problem.
Chuck 

Mike,
Don't know the answer, but sounds like an overly tight chamber.
Chamber cast might tell the story. .455" is about right for the base of a .303 cartridge.
SAAMI dimensions for max. cartridge and min. chamber which shows the chamber a couple of thousands larger.
Not able to attach SAAMI drawings, maybe someone can.
Chuck

The  case full of black powder along with the bullet provides a very different internal force. You are using a propellant that basically carries its own volume of "Cream of Wheat" built into the inefficient burning black powder. The sharp black powder grains tend to grab each other and the case walls creating a bit of obstructive force.  In some situations with a wet chamber or cannelured brass this force will actually tear off the front end of the case.   

SgtDog0311 wrote on Jul 27^th, 2016 at 10:32pm:

I use a very liberal dose of Bullseye and a paraffin plug. I have formed many thousands of brass. For a lot of cartridges I have fireforming barrels. If I have to expand the necks I wait until after fireforming.

P O Ackley (who knew a thing or two about fire-forming) recommended "good, snappy charges" in order to blow out the case to full size the first firing and avoid the wastage and exasperation that you are experiencing.

It is relatively easy with "improved" capacity cases of the same caliber--all one needs is the standard loading, with bullet, for the unimproved round.  Blowing a case out to a different caliber, or worse, a straight-wall case, especially an obsolete one, is not so straightforward and getting the proper charge in the absence of a bullet is simply a matter of experimentation.

I would recommend that you take your powder measure to the range, with de- and recapper, filler and a sheet of wax.  Start with the powder charge you used to get your shells this far and carefully dial up, one case at a time, until they are blown out fully.  Use that charge to finish up the intermediates and the rest of your cases.  Take good notes so you don't  have to do this over again, at least with this caliber.

Even if it is a blackpowder cartridge, I would go with smokeless powder and a filler, as it is easier and cheaper for this application.  You don't have to clean the not fully formed cases for the next try, and you can dial in whatever pressure you need to get the case formed.

Expect uneven case mouths and a need for a little trimming to even up.  Don't get discouraged.  It took me a couple trips to the dump before I got my .30-30 to .38-55 load down (9 gr Bullseye and Cream of Wheat to top of annealed case, wax wad to hold it in).  I would not expect that load to work in a larger capacity case, like a .303 or .30-40, but it would be a starting point.

Reverend Al wrote on Nov 22^nd, 2016 at 3:21pm:


When I built up cartridges for my Pacific in .40-85 I also used the 9.3x74R cases. But I used various reloading dies to get the case mouth opened up to accept the .410" bullets I loaded. I have a 330 grain mold I use in other Ballard .40's, so I loaded that bullet in the cases. 
Prior to shooting the cases were a little wasp like in the middle, so I knew they'd need to blow out. But I decided to try a charge close to what I'd shoot, and dropped my charge of 2400 powder and seated the bullets. When I fire formed the cases, I tried to shoot as well as I could hold, just to see how they grouped. Surprisingly they kept groups under 3" at 100 yds., so I was pretty pleased to get that during fire forming.
I found I needed to be pretty careful chambering cartridges, or the rim would slip under the extractor. But extracting cases always worked out well, with none slipping off the extractor.