pauleberly wrote:Texas Sheepdawg wrote:You also have to keep in mind the rifle twist of each individual rifle. The heavier bullets do better with the faster twists. But this also increases PSI, so you really need to be mindful of who's shooting what loads in what rifles. I've already noticed that my 230 grain FMJs loaded for my AR are screaming out of my single action and bolt action rifles that have the 1:16 twist rate. And they are showing some considerable pressure signs. Think on this. A 230 grain FMJ at 2700+ feet per second. That's not just meeting the TKO factor of the 375 H&H..... that's screaming insanely past it. And the pressure signs were equally frightening. So always consider the twist rates and factor in the faster twist rate is going to raise pressures.
I have a factory 450 bushmaster upper with a 16 inch barrel. What is the twist rate?
Faster twist means the bullet accelerates out of the gun faster, causing a greater velocity? Wouldn't you want a fairly high twist rate then?
And when you mention the TKO factor, that is the potential killing factor that a bullet has upon an animal correct?
And when you mention 230grain bullet at 2700+ fps, that is at the muzzle correct? I am assuming (but do not know) that muzzle velocity and the velocity at lets say 75 yards is much different. If we are killing animals at 75 yards, wouldn't we want the bullet to be traveling at a faster velocity at 75 yards to have more energy when it collides with said animal for more foot pounds of energy?
Lots of good questions. If your upper is a factory "Bushmaster" upper, it's 1:24 twist.
The faster the twist rate, (1:16 is faster than 1:24), means how many 360° revolutions the bullet rotates on its axis AS it is traveling and leaving the barrel. The slower rates are sometimes not fast enough to stabilize a heavier projectile on its axis. The faster twist rates tend to spin the heavier bullets faster so as to make them more stable and therefore more accurate in flight. However, twist rates also cause pressure changes, as it takes more pressure in the faster twists. The higher pressure ALSO means that there could possibly be a marked increase in velocities. But this may or may NOT be a good thing.
As for TKO, google Taylor Knock Out Value Formula.
Once you learn to use it, compare your favorite most used cartridges to the 450 Bushmaster.
Learn more HERE.
https://en.m.wikipedia.org/wiki/Taylor_KO_Factor