So I am still new to casting and 12g loading. Finally got some lee 1oz slugs made up and wanted to make some dummy rounds to see how they load.
I am using data from Hodgdon site below (Rem STS hulls)
Lead Slugs 12 1 oz. Lee Precision HS-6 Win. 209 WAA12SL 36 10,200 PSI 1450
(same info as on the sheet that came with the mold)
When I seat the wad and slug (30 psi on sizemaster) I am getting a huge buldge in the hull, not allowing it to chamber.
My cast slugs are around .690 diameter and I am using Claybuster CB1100-12 ( which says same as WAA12SL on the bag)
What Am I doing wrong? I even tried loading a live round, thinking the powder might make a difference, but still same buldge.