Home Forums Hunting & Shooting Express Rifles and Big Bores Only 505 Gibbs modern powders.

I don't have it handy but Phil Shoemaker had an article on the 505 in the August 1999 issue of Handloader.

Even though RL15, Varget and H-4350 are on the fast side for the case, 600 gr @ 2300 should be no problem with those powders. In my 500 Jeffrey my starting load of 100 gr of RL15 pushed 600gr 2200 fps.