As I have previously posted, I have a Commission 88 carbine that has been sportered and rebarreled to 6mm Lee Navy, using a commercial Winchester 1895 Lee Navy barrel. One of the members here was generous enough to loan me a set of 6mm Lee dies as well as throwing in some .220 Swift brass. Forming the Swift brass into Lee brass was a no brainer, but the short case really bugs me. I'd rather have proper length brass, but sources of it are out of stock or extremely expensive. I've read that 30/06 brass can be reformed, with a little tweaking. I have an abundance of WW2 30/06 brass, so I tried my hand at it. I decided to do it in steps, so with some trial and error I came on the combo of running the brass through a 7x57 die to start, then a 6.5x55, then a 6mm Remington, shorten to 6mm Lee length, then run it through the 6mm Lee die. You can only run it through so far, then you have to reduce the base by metal removal. I'm chucking it up in the drill press and filing down the step left at the base until I can finally run it completely through the Lee die. I am not touching the rim, as the rifle is using the 8x57 bolt head and needs all the rim available. I ran the Swift brass through the gun, and it extracts fine. Hopefully after firing there is enough rim to facilitate extraction. After getting the brass to the point of being able to run through the Lee die, I still have a lot of polishing before it will chamber in the rifle.
After running the brass through the 6mm Remington die and shortening it, I noticed that base to shoulder length was nearly identical to the Lee brass I formed and fitted, with a slightly different shoulder angle. So the thought occurred to me: why no just rechamber to 6mm Remington? Using the 30/06 brass would give me the longer neck that I need and no mods would be needed to the base of the case. I wouldn't be damaging any collector value, as the rifle is already a mix of parts. I've ruined about 10 rounds of brass playing with it, and making the 6mm Remy would be SO much easier. So, any opinions? It goes without saying that the load data I use will not approach the 6mm Remington pressures.
This is after running the brass through the Lee die for the first time. You see the band at the bottom that needs removed before I can finish the reforming process.
Here I have the steps I'm taking to form the brass: 30/06 parent, reform, to 7x57, reform to 6.5x55, shorten to Lee length, reform to 6mm Remington, reform to Lee, last is .220 Swift reformed to Lee.