Case belling:

[Wild Nick Billock SASS #53521]

Dillon reccomends 20 thousands of an inch, but this got me thinking. 20 thousands is about 4% of the diameter of a 45 colt case and a little over 5% for a 38 special case. A larger bell will tire the brass more quickly, so is it better to aim for a fixed percentage, say 4% to make the smaller case last longer or does it not make much difference? What's a reasonable tolerance for the amount of bell for a normal case life?

[Garrison Joe, SASS #60708]

Applying either a fixed or percentage diameter increase is usually not what most reloaders do when they adjust their mouth expansion die. Most reloaders set the minimum belling that will allow the bullet to be seated without shaving lead (for lead slugs) or causing crumpled cases. Any more bell than the minimum for good seating IS going to work the case more than is needed. The usual rule of thumb is start with the amount of bell that you can just tell with your fingers is no longer a straight neck. Add a little more if the bullets or cases are damaged.

 

If I was pressed to pick a numerical expansion of the mouth compared to the neck, I would think about 0.005 inch would be where I would start - not 20 thousandths.

 

And a Lyman M die often has the BEST expansion button profile for our lead slugs. The RCBS Cowboy expansion die tries to copy that general profile, too, if I remember right.

 

Good luck, GJ

[Adirondack Jack, SASS #53440]

JUST enough so ya don't shave lead when ya seat bullets and no more. Don't make it harder than it is.

[Cpt Dan Blodgett, SASS #75655]

corollary don't crimp any heavier than necessary

[Gold Canyon Kid #43974]

Applying either a fixed or percentage diameter increase is usually not what most reloaders do when they adjust their mouth expansion die. Most reloaders set the minimum belling that will allow the bullet to be seated without shaving lead (for lead slugs) or causing crumpled cases. Any more bell than the minimum for good seating IS going to work the case more than is needed. The usual rule of thumb is start with the amount of bell that you can just tell with your fingers is no longer a straight neck. Add a little more if the bullets or cases are damaged.

 

If I was pressed to pick a numerical expansion of the mouth compared to the neck, I would think about 0.005 inch would be where I would start - not 20 thousandths.

 

And a Lyman M die often has the BEST expansion button profile for our lead slugs. The RCBS Cowboy expansion die tries to copy that general profile, too, if I remember right.

 

Good luck, GJ

 

+1

 

I have found only one supplier of bullets to have such soft lead that I have to increase the belling more than what you can feel but not easily see. For that very soft lead I have to increase the belling a small bit. These soft bullets (ones with built in dings) are very good bullets just a bit softer.

[Virgil Ray Hality, SASS# 37355]

+1 for what Garison Joe said.

 

Also, when you get around to 45=70 or other expensive rifle brass, annealing the case necks will help with longivity. I did this with 38spl many years ago and some 44-40. Its not worth the cost/hassel for cheap brass. I loose far more brass that is not picked up at a CAS match, than I loose from split cases and cracked necks.

[BIG TIM]

Being a blacksmith I understand the movement of metals and the stress that this causes....That being said I also bell just enough to not shave lead when the round is pushed into the case. I have found that by doing this I have pretty good case life and can reuse the same brass longer. I also crimp just enough to not allow the lead to push down into the case. The less you move metal the better.

[John Boy]

Being a blacksmith I understand the movement of metals and the stress that this causes.

The less you move metal the better

That's why I bell CAS reloads so that 1/2 the width of the base seats inside the case before going over to the seating die. Think about it ... if a bullet is seated on the edge of bell, the seating die is going to push on the base. The base will not be square with a sharp edge when seated.

 

For BPCR reloads, shooting for accuracy, the case is expanded so there will be 0.001 to 0.002 tension on the whole bullet. A slight bell can be made, the bullet finger seated and the bell removed with a slight tap of the crimping die or the resizing die extended high in the press