I have tried a .303 British die. It didn't quite work. Like you said, the die would have to be shortened a tad. I did the .308 Winchester die trick with the washers and that worked, but I had to expand the case necks a little because the .308 die was a tad too small for the .312 bullets. I wonder if there's a combination of various Lee die parts I could put together to make a die that would work normally? I already have a spare .303 British mandrel. I may just end up going to factory route though. Such a shame, you'd think Lee would have one on the market already.mysticplayer said:You could also try a 303 Brit die. Don't have dimensions in front of me but they seem similar. You may have to shorten the die a bit but could be made to work.