[Brian Pfleuger]

I have a theory that you should find the seating depth your bullet likes BEFORE you tweak the load.

Someday, I'll get around to testing it.

The idea came from discussions with UncleNick, might well have been his idea, I don't remember now.

Least ways, the theory is that the load you find is based on barrel time. Once you have the load and then start messing with seating depth, you are simultaneously changing barrel time. Two variables, hard to know what's happening.

So, start with seating depth using 90-ish % charges of Trail Boss. Trail Boss burns almost instantly and at pressures much lower than normal rifle loads. Both characteristics reduce barrel vibrations and decrease the importance of barrel time. Tweak the seating depth until you find what works best and THEN do the normal charge sequence. Only one variable, should be easy(er) to isolate.