But it is far less than Maximum by Hodgdon's own web page. "Load to bottom of bullet" is maximum, and reduce 30% and work up. 6 grains is about 30% less than a full case (minus bullet depth). I have fired a few with full case (Hodgdon's maximum). They were stout, but still no signs of pressure and cases fell out of the chambers. Published trail boss loads are "gamer loads" in my opinion (giving about 650 to 700 fps with a 200 grain bullet). My bottom end, by the manual, Unique loads are stiffer than the 5.0 grains in a Schofield case (about 60% of volume less bullet depth). Hodgdon even says it is impossible to overload a Trail Boss load... Lawyers have other ideas, maybe.
I have been reloading for over 40 years, and shooting and reloading for SASS for 23 years. I have watched the conventional wisdom go from good, solid loads in SASS, to load as low as you can go. Suddenly if you choose to load full loads it is considered aberrant behavior.... I take Hodgdon at their word. Our firearms are all SSAAMI spec.
You march to your drummer, I'll march to mine....
I know this is an old post but I wanted to add my test results. I used the Pressuretrace II strain gauge system.
Using Buffalo Bore's "Heavy" 44-40, said to be withen SAAMI MAP 11,000psi, I set this load at 11,300psi...SAAMI MAP is 11,000psi
Buffalo Bore's 44-40 Heavy is certainly more powerful than any other factory loaded 44-40 ammunition...thus the "control" and gives me 1,350fps.
6.4gr of Trailboss under a popular manufactured 200gr Magma hard cast bullet (the same style as BB uses) produced 7,224psi
9.3gr, a case capacity load where the bullet sits firmly on top of the powder, gave me 1,250fps from my 20" testing barrel @ 15,182psi. That would be close to 18,000cup with a SAAMI MAP of 13,000cup. The is no magic formula to convert psi/cup BUT factory High Velocty loads produced 22,000cup which would be in the ball park of 19,000psi
Trailboss also says that if a load is not supplied for a cartridge, the caseload formula will work. Well, there is a max load data supplied and it is 6.4gr...about a 30% reduction from max psi of 11,000.
I also tested 40gr/w og Swiss FFG with a .19-.21 compression in original semi-balloonhead cases which resulted in 14,284psi with handcast Lyman 427098 soft lead bullets @ 1,373fps. Same loads with Goex FFG resulted in consistent 12,650psi @ 1,300fps and in modern Starlin brass.....10,000psi-11,000psi @ 1,250fps. Swiss FFG in modern brass required more compression and pressures dropped to 8,8000psi @1,230fps
For what it's worth