Thanks, BR.  My burn rate list says Accurate 2520 is just a smidge slower than IMR-4064 and a good bit faster than IMR-4320.  Jacketed bullet loads in the 34 to 36 grain load range have been in use since the 1930s for US Krags and the '06.  My guess is that something else was amiss.  Those case necks did not look kosher.  Bullets for a Carcano?  IIRC, those run .266-.268 and come in boxes that say 6.5 mm.

That Lee Navy makes me want to cry.  I spent the better part of 3 years trying to find a good one at a price I could afford.  I quit looking when those accidents appeared on the net.