Choosing a Powder for a New Cartridge

You just purchased your new hunting rifle in a cartridge where you have no loading experience. What powder do you choose? When you look at reload data, the list of powders is usually long, and any one of them might work great. But here is the trick to hone in quickly on the ones that may work best. 

First, choose the bullet for your intended use. Review the reload data to find the velocity level you wish to achieve. As you look at the powder charges, chances are very good one of the powders that meets your velocity criteria shows a “C” beside the maximum charge and/or gives one of the highest velocities. The “C” means a lightly compressed charge of powder. That is an ideal situation, as maximum or near maximum charge weights that yield from 95% to 103% load density tend to give the most uniform velocities, as well as top accuracy. 

I’ve yet to see a benchrest shooter whose load does not completely fill the case, as well as give top velocity. The same holds true for a varmint shooter, case full or darn close to it. Along with that particular powder, the powders listed closest to it on either side will likely be in that 95% to 103% range as well. This is a great place to start. Simply start with the beginning load for that combination and carefully work your way into the maximum, at all times watching for case head pressure signs. You can save a lot of shooting by carefully going up in 1/2-grain increments at a time (in mid- to large-capacity cases). Fire only two rounds of each charge level, each pair at a different target. Shoot slow enough to not overheat the barrel. Some of these two-shot groups will show a willingness to group closely. When you find shots that group tightest, load several rounds and then shoot five-shot groups for verification.   

I do not have one rifle that doesn’t group the best somewhere near the max load. Should this not provide the accuracy required, either change primer brands and repeat or try one of the powders on either side of the one you just tested. Chances are very good one of these will lead you to a load that meets your expectations.