Mainer, the Lyman 379449 is a .379 diameter gas check bullet that is 1.060" with check, has a meplat of .220-.230 ahs three lube grooves and a crimp groove. Book says it weighs 264 grains as cast, I'll have to take their word for it, my Lee scale only goes to 110 grains. It is not a bore ride design although the nose is a smaller diameter than the shank, this is most likely to allow for easy feeding through lever action designs. I have the Lyman Cast Bullet Handbook copyright 1972, it shows the Lyman offerings to that date, and includes this bullet. I am using FWFL (Felix's World Famous Lube) a homemade lube that is every bit the equivilent of any of LBT's offerings. The only times it has allowed a leaded barrel is when the bullet has not fit the bore. It is good to at least 2400 fps, so long as the bullet is up to the task. I have driven this bullet at 10 BHN to 1900 fps without leading, but find the 1700 fps loadings to be more accurate. That would probably change with a harder alloy, but then I would lose it's softness which I like for a hunting bullet.