S&W mod. 25-5 .45 Colt with 4" bbl.

[rockquarry]

Is the advantage of a 300 grain bullet over a 250-260 grain something real or something perceived to be real? If the heavy bullet is more accurate, that's a real advantage.

 

[USSR]

I want to load a 265 grain hardcast keith bullet over 13 grains of Hs6, would that be OK? Any reply welcome.

Yep, that load falls within the recommended 23k psi pressure limit of your N frame. I have used it and John Linebaugh highly recommends it.

Don

 

[Snapping Twig]

9g Unique and a 255g RNFP gives me 900fps which is just right IMO.

You can do a lot with that and it does not stress the revolver or the shooter.