Re: Case neck tension w/ std. expander dies
There's a cheap tool called a lyman M die that might work really good for you. It would be like using your neck turning expander but it has a slight "step" at the top of the spindle that slightly bells the case mouth for seating of lead bullets. It's available in almost any diameter and costs about $12.00. It's great for ironing out new brass. Did you ever wonder how the factory seats a bullet yet the case mouth is never chamfered?? I'm guessing they use a tool like this and bell the case mouth slightly, seat the bullet, then crimp it shut. NOw, I have another theory that I think could enhance accuracy of your normal "loose chambered" hunting rifle. Everyone has heard how in match grade rifles the chamber is really made to tight tolerances and the case mouth barely expands during firing. (alot of times I've heard you can almost re-seat a bullet without resizing). Well what I'm thinking about is leaving the case mouth ever so slightly "belled" and using this slightly oversized area to center the cartridge better in my hunting rifles. (I may not hunt this way, but think it could/should slightly enhance accuracy) Tonight I loaded some 300 wby shells. Cartridge diagrams say the neck area should be no more than .337" thick. We'll, with the bell at the case mouth I'm at .340 and they chamber like butter. It almost has to have a centering effect on the cartridge as it sits in the chamber.
Any how I've seen others who have taken a 3 step approach to sizing. They decap with a universal decapper, they size the shell in a fl die without the expander spindle dragging through the case mouth. Then, they use the lyman m die to bring the mouth back to dimension.. It sound like it might take alot of extra effort but I'm guessing the whole process might add 5 minutes to a 20 case reload?? If you are trying to create some good rounds you might like this. It's also worked good for me when using moly or barnes xlc bullets to keep from shaving coatings. I'm kind of a .308 guy with about 5 rifles from 30-30 to 300 wby so I get lots of use out of that one die==plus I have marked down where to set the adjuster so I only "bell" about the first .010" of each shell--much like chamfering.
Well--just some rambling thoughts but I do know some quality long range shooters that also use this tool and swear by it.