.458 bulging Starline

[Kurt]

Doug I don't know what your loading procedures are so I really cant say why your having a problem. I have two .45 Shiloh's and both have a .482" chamber wall at the case mouth and I also have the reamer drawings Shiloh used and are using. .482 chamber wall should take a .458+ diameter bullet with even Norma brass that has a thick neck wall.

If you seating the bullet and compressing the powder when you seat it the bullet will expand and cause that bulge. If your compressing the powder using a compression plug and compressing the powder a lot this will also cause a bulge.
If you don't have the seating die adjusted properly and it starts up into the crimp portion of the die before the travel of the ram is at the top this will also start a bulge.
It's hard to say with out knowing your loading technique.
Another thing, If you have a special order tight chamber they make for the PP then you will have a problem seating a bullet and get it to chamber.

Kurt