The risk of reloading big bore cartridges is in all cases, without a test barrel, very high ! Varget is a fast burning powder in the class of IMR3031, TU3000 or R902/R903. All this powders are recommended and in our countries the first choice for reloading cartridges like the 360NE or the 9,3x74R ! With low burning powders i had a lot of ignition problems with hanging fire and in many cases a bullet fixed in the barrel after only ignition of the primer ! Not very safe too ! THE PROBLEM ARE THE OLD RIFLES THAT WE USE ! Better we dont reload this big old cartridges and use factory loads ! I shot a lot of factory cartrdiges caliber 577NE from WR and a few caliber 600NE from Kynoch . Recoil is very stiff, what they put inside ? Are this maximum pressure factory loads safer in old rifles ? I dont know !