I have used 311291, 311041, 311466, NEI 180 RNGC, SAECO custom 190FNGC, and, believe it or not, 311284 220gr. RNGC in the .300. Powder charges that I was successful with are all over the map, but two that gave consistently good results in all of them are 10 gr. Unique and 14gr. SR-4759. Note however that I didn't spend much time working up full throttle hunting loads, being satisfied with mid-range loads for fun shooting. Also, due to the short neck, as by now I'm sure you're aware, cast bullet use is problematic, but not overly so. Since my test vehicle was/is a M1920 bolt gun I loaded the cast bullets at maximum length to engage the rifling and minimize case intrusion without heeding "normal" OAL and eschewing magazine feeding. Most of the tested bullets ended up seated so far out that they wouldn't feed from the magazine. For my style of shooting, that didn't bother me in the least but I suppose it would some people.
If I were to work up a hunting load with cast bullets for the .300 I would go with a 190-200 grain flat nosed number and use powders from one end of the spectrum or the other that will allow .30/30+ velocities without high pressure. That's to say something like 3031 or 4350. I don't know why, but I never got great results with the medium burners at +2000fps in any of the medium capacity .30 cartridges with lead bullets, but relatively fast or relatively slow ones do well. Cast them soft, in the neighborhood of 11-13bhn (wheelweights + a smidge of tin), for good expansion at velocities down into the teens. Cast bullet shooting is all about compromise. The compromise here is soft alloy = low velocity (2100 fps is about max) hence the heavy-for-caliber bullet to get energy levels back up to where it becomes a reliable killer again. A 200 grain cast bullet at 2000fps is a far better killer than a 150 grainer at 2000 fps. A 190-200 grain cast bullet at 2000fps MV is smack dab in the realm of the .303 Savage and we all know that one is no slouch in the deer woods. Rest assured, a lead bullet of 11bhn at that velocity will expand like the classic mushroom shape.
Why use cast bullets? A)The challenge of finding the right combo of alloy/powder/seating depth/bullet design for success. B)Cost savings. Low velocity plinker/fun cartridges cost next to nothing to load, compared to case-fulls of powder + store bought jacketed bullets. That translates into spending the day at the range and firing a couple hundred shots and not depleting the wallet or bruising the shoulder. And C) Perhaps the most important reason of all: since we're talking about shooting rifles that are getting increasingly more valuable and which aren't made anymore, a steady diet of cast lead bullets will do virtually zero harm to one's bore. You'll never wear out the rifling or burn out a throat shooting cast bullet target ammo.
That's why, in 1000 words or less
, shooting cast bullets in the .300 seems right. (The same argument can be made for the .250, but due to the bullet weight/velocity restrictions I would be loath to use cast bullets in it for deer hunting.)
