Once in awhile it's good to think outside the box.jryock wrote:Couldn't you use the shape of a heavy bullet and use non-lead materials to make it lighter? Projectile manufacture is something I know very little about.
Most hunting calibers are "high velocity," meaning, the muzzle velocity for most are at or well above 2500fps. The range is probably 2500-3500 fps with 2700-3000 being typical. Bullet manufacturers have always oriented ideal performance towards striking velocities around 2400-3200 fps.
So, these bullets work horrible at the slower velocities of the 300Blk. That's why the early recommendations were to use varmint bullets or lightweight bullets (often one and the same in .308" caliber) if you want expansion in the 300Blk.
Personally, I think bullets designed for calibers such as the 30 Herrett, 30-30, 7.62x39 and similar rounds are a better choice, but they are hard to find or have diameters or nose shapes which are just not quite right for the 300Blk. (This is where I was coming from with the 130-135gr bullet I described above.) A side benefit to these is they are inexpensive, because they are simple, "old-technology" to make -- a lead core in a copper alloy jacket.
Now, going towards the new technology, an idea I've been playing with is a super-thick jacket with hollow core which goes about half way down the bullet. Jacket walls would be about .115" thick, leaving a gaping .078" cavity. Walls would taper thinner towards the nose and "crimp" onto a hard plastic tip which would be shaped to initiate expansion on impact. This is a starting point -- the dimensions would have to be tested and modified to find the point where reliable expansion is obtained at 300Blk terminal velocities, but this should expand better (sooner) than the Tac-X. The big downfall in my eyes, is this will be too expensive (about the same as the Tac-X, so why bother? I'd rather have the cheaper cup and core bullet...