There is always this from Varmint Al's page:
POLISH THE DIES.... I polish the inside of my rifle reloading dies. Most die manufacturers leave the die bores smooth but not polished. A polished die will resize with much less axial force than one in the as-received condition. I disassemble them and put a little Flitz on a cotton bore mop held in a drill motor and polish each one for 30 seconds or more at a 300 to 600 rpm speed. Sometimes I have to wrap a paper towel around the swab to get a good fit. Then I clean all the polish out with hot water and dry with a paper towel wrapped around a clean cotton swab. The polishing process does not remove a measurable amount of material, but results in smoother operation, minimizes the scratching or scoring of the brass, and minimizes crumpling problems when I use them while forming wildcat brass.
Flitz is slightly more aggressive than JB. I took a piece of mild steel with a reasonably smooth finish and polished it with Flitz and JB. The left end was polished for about 2 minutes at 500 rpm with Flitz and the right end for about 2 minutes with JB. There is no detectable decrease in the diameter on either end measured with my high-precision Mitutoyo Micrometer. It was a very easy test. Try it for yourself.
WHY POLISHED DIES HELP.... When you are resizing brass, there are combined forces involved. In necking down a diameter, there is a radial force moving the metal toward the center and an axial force, produced by friction, that tends to shorten the column length. For larger changes in diameter, the radial force increases. Since the axial force is equal to the friction coefficient times the radial force, a corresponding larger axial force is produced. High axial forces can crumple the brass when its critical buckling load is exceeded.
How do you minimize the axial force? You can reduce the axial force by reducing the radial force when the reduction in diameter is taken in smaller steps. But this takes a series of separate dies and costs more. If you have only a few dies at your disposal, you can also reduce the axial force by reducing the friction coefficient. The inside of the die can be polished with a metal polish like Flitz and used in conjunction with a thin film of lubricant. This will greatly reduce the axial forces and minimize possibility of buckled cases.
Here is the link:
http://www.varmintal.com/arelo.htm#Polish
I've done this with several dies, and have used his process to restore dies that have started scratching, instead of replacing them. I did 3 sizing dies for a friend and he's still using them almost two years later.
This might help in your case.
Fred