I reload a few types of slugs for my 12 gauge, but I just bought some reloading gear for my 20 gauge and figured it would be fun to load slugs.
What I am finding is that there is very little in the way of slug data for 20 the 20 gauge.
I'd like to use wad slugs as I am using a gas operated shotgun (saiga 20) and the gas vents are a pain to clean lead out of.
What I have is:
Lee .575 RB (285 gr.)
Lee Minie .575 (470 gr.)
Lyman Sabot .576 (350 gr.)
I don't have load data for the lees as they are intended for muzzle loaders, but they are the same size as the lyman.
What I'd like to know is how much constriction is safe. The wads I have measure .03 thick on the petals (give or take .002) so the combined thickness with the slug is .635 and my barrel at the choke is .615. As I understand it, shot actually generates a lot of constriction, is this correct?
Would a shot load of a similar weight be a logical starting point? Or are these totally different items?