I have been using 20g 4759 powder for my 40-65 loads and a 405g bullet and a cotton cover. I have been using Rem 9 1/2 primers. I have Rem 9 1/2 magnum primers. Is there any advantage or disadvantage of using magnum primers with 4759?
I used magnum primers with 5744 powder in 45/70 loads in my Trapdoor, because I had found so much unburnt powder with standard primers. I have no signs of unburnt powder with the 4759 powder, I was just wondering if there would be an advantage in using magnum primers,

Quote:
No disadvantage but no advantage with 4759.  Ball powders and the new 300-MP, a spherical powder work better with magnum primers IMO

The vendors when testing the various powder loading data will say when magnum primers are required

Not a single shot rifle. I do use 4759 @ 20.0 grains shooting a Lyman 314299 out of a Finn Model 27 Moisin Nagant with a truly beautiful bore. Rest of the rifle ain't bad looking either. And as for primers use the Winchester large rifle primer. Never had problems igniting this powder with these primers. Frank