Abundant 'Square Pegs'
Date: Jun 28 2006
One of the oldest cliches in the world concerns trying to fit a square peg in a round hole. Well, quite a few of the questions we get here involve exactly that. Recently, for instance, I was asked by a subscriber to suggest some loads for Ramshot TAC in the .50 BMG cartridge. Why? The inquirer had a whole bunch of TAC, and he'd just bought a .50 BMG.
This is like trying to pound an octagonal peg into a screw hole. TAC is a medium-burning rate powder, about like IMR-4895. It's designed, like IMR-4895, to work in moderate capacity cartridges with medium-weight bullets. Ideal combinations are the .223 Remington with 50-grain bullets or the .308 Winchester with 150-grain bullets.
The .50 BMG is a huge cartridge that shoots very heavy bullets that are quite long even for .50 caliber. Consequently even powders we normally think of as very slowburning (such as IMR-7828, Hodgdon Retumbo or Ramshot Magnum) don't work very well in the .50 BMG. It's so specialized, in fact, that Hodgdon even developed its own powder specifically for use in the cartridge. It's named, oddly enough, Hodgdon H-50BMG.
At the other end of the spectrum, I've also gotten requests for loading data with H-4831 (a fairly slow powder) in cartridges like the .30-30. Why? You guessed it: The reloader had a lot of H-4831. Yeah, you can fill a .30-30 case with H-4831, and stuff a bullet on top of it, but the velocity will be really, really low, because only perhaps 50 percent of the powder's energy will be used.
Accuracy will also probably be lousy. Most powders are designed to burn most consistently at certain pressures. If they're burned at 25,000 psi rather than 55,000 psi, they'll probably produce erratic velocities – and a lot of the powder won't be burned at all. It's simply a waste of good H-4831 to use it in a .30-30. Buy some IMR- 4895 or Ramshot TAC or some other appropriate powder for the .30-30 and save the H-4831 for your .270 Winchester or .300 WSM, where it works great.