I would not pull the the trigger with one of those loaded in my TC Contender or Ruger. Those are HOT rounds for a .45 Colt. Be careful of where you store them as they would shatter an old Colt or clone of one.
Which is why you shouldn't shoot anything but Gunpowder in an old Colt's SAA. That even includes a lot of the post 1896 models once they started marking them with the "VP" (Verified Proof) symbol to designate they were capable of shooting nitrocellulose powder. Steels were constantly getting better up until the 2nd World War.
A lot of knowledgeable people in the early 20th century used to recommend using Semi-Smokeless powder in old SAAs before it went out of fashion and ultimately production in the '30s. You used to be able to get .45 Colt, .44WCF, .38WCF, etc. cartridges made by UMC, Peters, Winchester and others with powders like Lesmok (semi-smokeless), or King's.
The beauty of Gunpowder is that you really can't overload a pistol cartridge, and the pressures generated are benign.
Why are we discussing nitrocellulose pressures and powders, I thought this was the BP forum on this site? Batteran's original post is useful to help with our understanding of BP and why it differs from Nitrocellulose.
For the last several years I have been reading with some concern about the growing use of substitute gunpowders like 777 in weapons it was not intended to be used in. We might be doing a disservice to many of the less experienced readers if we act like it is no big deal and especially if they have been using gunpowder as it was intended. That is either a full compressed case of FFg or even FFFg of real gunpowder or a recommended measure of BP in a percussion pistol.
Modern Inlines are extremely strong and that is the intended market for the newer substitutes. A oft repeated warning about use in pistols or even toggle link rifles is probably in order.
~Mako