James I appreciate the feedback - not caustic at all.
I have been struggling, albeit a bit at a time, for many years. I have tried various slugs on and off for about 30 years but not really looked at it like a project. I have mainly used traditional Fosters and book loads with minor alterations like paper patching slugs to get them to bore size. I really haven't looked deeply into the finer details until recently.
As you point out, and maybe it should be more obvious but I hadn't really thought about it, are the chamber and forcing cone designs. Even more of and issue with a 2 3/4" hull in a 3" chamber so forcing cone to deal with and a long jump to get to it first! I had never considered how much the slug can skew in that distance which may well help explain my poor results with the short Lyman Foster slug.
Like I said, I have kind of worked on this for a long time but not as seriously or in as much detail as I should have. I have probably learned more in the last 6 months than I have in the last 29 1/2 years! There are many people here such as yourself with far more slug shooting experience than I am ever likely to get and I appreciate them sharing there experiences and knowledge.
Longbow