Hi all, I went to the garage to turn a bunch of cases for the Howdah. I have a piece of 1/2" round stock that I turned a small pilot on the end to stick through the primer flash hole. I have the round stock held in the lathe and used a pipe fitting with a hole drilled and tapped for a folt to hold the case on. My problem is that I am not getting uniform case wall thickness. I have to turn the cases down to .735" and cut at 1.6". Any thoughts on how to keep it more centered? On some of the cases then the primer flash hole is not centered, so I just don't use them.
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LAR--On most BMG cases the primer pocket and flashhole are off a little, from my experience.The rim on the other hand

on 80% of the cases is fairly concentric with the base above the rim.Do you have to make rim smaller.If not get a good strong collet for the rim and you can machine and cut it off easy.Even if rim had to be smaller you could do that

after by chucking cut off case on a mandrel for support into

lathe jaws(turn mouth in) and do the rim if needed.Now you say you have to get case down to .735,

so do you do it with a straight machining cut the length

of the case.That would make it thin.You should turn base area at a slight angle out, getting solid base to .735 and then get the .735 size for sides in your die.That is what I do in making my 700 HE case and gets

me sidewalls just above the belt of .060. IE; the idea is to get enough off of the solid head base, the least off of the sidewall, and then the die goes down over the base

without huge force needed and case is right size with thick sidewalls.Need any help call..Ed.

Ed, I have been turning it straight down, then cutting to length. The barrels don't have much of a provision for a rim. I could just turn the rim the same diameter and headspace off of the mouth. The inside of the case after cutting to length just happens to be the perfect size to seat the 1oz 12ga slugs. I am soldering the primer pockets closed anyway, so maybe I could chuck the casehead in the lathe, then turn out the primer pocket hole to get a true center, then make a new mandrel and go from there. I tried some CBC 16ga brass, but the chamber appears to have been made for a coiled brass case that is much thicker than the CBC brass so I would have had to neck the mouth down to hold the bullet. I'm thinking that the BMG brass will be much stronger also. On my 577 Pinfire howdah the chamber wasn't cut for a rim at all, so I'm thinking that it probably headspaced on the pin or maybe the mouth. I have some 28ga CBC brass for it, but haven't even shot it yet.

I just had a thought for the BMG cases. Maybe I could size them down like you said, turn the rim and base to dimensions, then inside ream and leave an inside sholder for the bullet to seat up against like on my 44 Auto Mag brass??????

How much force does it take to form your HE cases? Maybe use a hydralic press for the initial forming??

Lar--You are right about BMG cases being the best.Once you get the machining and sizeing right, with dependable headspace system, they will never wear out.I use Ammomaster
press.To size case without damaging base, you machine base
first down to the .735 next to extractor groove and out at a slight angle toward front of case. Then your sizer will do the rest without having to use huge pressures.Of course you can use hydraulic but if you try to push to much brass over the base you may cause damage, will make base crooked to the side, and/or wrinkle up the sides.I will post a picture of a sectioned BMG case with the machined taper
so you can do the same.Have a few from my experimenting.
Get it on in couple days.Then after machining, sizeing,and
all the rest is done you reverse case with support mandrel inside, into lathe and do the rim.Ed.

Here is picture of BMG case turned on a slant on the base on the left.Right at the groove it is .735 and tapers out. That way a die can form case and slide down over base easy,
in the forming process and the inside corner will not be
changed or pushed into a too sharp of a radius.
IE you won't change radius that much. Right case is one of my 700 HE belted.You can see the thick sides above belt and proper curve in the corner for strength.I use unfired Lake City or similiar brass that has the large radius.That is why I section cases to see which is the best to use, and make sure designs are strong.I have another's design of belted case, where they pushed the belt on and made the inside corner real sharp.They had to use brass that had a real sharp radius to start with, to be able to push the belt on.Not the best I think for high pressure.And the belt was a tenth of an inch further up the sides than mine.My belt is near base so it won't expand with repeated firings.Their push on belt is on side and when it expands from firing it is hard to size it back.Ed