When setting the belling die, I keep a bullet of the type I'm planning to load on the bench and progressively screw the belling post in, run a case up full ram stroke and check whether I can get the base of the full bearing diameter into the case mouth so that it sticks in the case a little bit - that is, the case grabs it so it doesn't fall right out. I do this repetitively, screwing the expander in a little bit at a time until I've gotten the expander set as above.

Usually I end up belling the cases just a tad more if I'm seating cast bullets so I am sure I'm not going to shave lead off the bullet with the case mouth.

I've never had any problem with having so much bell that it interfered with case entry into the seating die.

Some dies it's more problem than others.  I had a lee seating die in 32/20 that caused problems. Chucked it in the lathe and put a bit more taper in solved the problem. 32/20 for a lever rifle store bought cast bullets I want to load fast no fooling with it.

However for my 38/55 I take some time to set the bell just right. It's a feel setting little more until you go too far then back off.   Lyman M die is the best way to bell. Other brand neck expanders don't have the easy taper Lyman's does. Lees don't work very well. I have changed the taper and polished Lees expander too improved the bell.  Not to be negative on Lee they are built mostly for jacketed bullets and not expensive. I don't need the best die for every caliber.  32/40 38/55 and 40/65 I do and use Lyman's 

Boats 

That's a good tip. Will save the address. Lyman would make custom expanders not sure they still do. And as I recall took a long time.

Mostly I start with one that's too big Reshape and cut it down to suit

Boats

The first thing that you need to do, before using a M die, is to make sure that the cases are the same length. If you carefully set up the die and you have a .010 short case, it won't get belled enough.

What I would suggest for copper (any neck tension) and GC bullets, with .002 neck or less  tension, is to chamfer the case mouth, at least 1/2 the neck thickness, at the standard counter sink angle of 82 degrees. I chamfer all my cases, at least 3/4 the neck thickness, even BS cases, it helps seal the case mouth.

Frank

"Home much do you bell you case mouths?"

I stopped belling my cases a long time ago. Stopped sizing brass. Stopped using any dies at all except to do an occasional corrective resizing operation. 

That's some funny spelling there. 

         Joe.

I don't bell the case mouth at all. I could never get the bullet to inter the case in a straight line. I use "M"s dies only. Lyman did make them but I don't know if they still do. I have several mad by them.

LONG RANGE wrote on Jan 13^th, 2016 at 6:31pm:


From what I've seen, the new Lyman M dies don't have the changeable pilots that my old long and short M dies do. So a lot more expensive to have multiple dies for various sizes. Why they changed a very good design is beyond understanding?