Safe, yes. But 850 fps will be about like throwing a rock. I'd try Unique or Universal. 5.0 grains of Unique with the Lyman bullet at 1.995" COAL gets you about 1050 fps at about 30K psi, which is a good balance, although at the cost of about 300 psi more muzzle pressure. It's going to be loud without a can regardless, just "less loud" than a hot supersonic load.