Do bullets with different lengths, vary in bullet length?

[brentn]

Just curious, but a bullet with 140 grains versus a bullet with 180 grains of the same caliber would be identical in size?
I know that the OAL of the cartridge with the bullet is always the same, but I've always wondered about length of the bullet itself.

I brought this question upon myself when we were talking twist rates in barrels and their affect on a bullet. Alot of people were saying that bullet spin is affected by weight of the bullet given a particular twist rate. Alot of people, credible people, were saying that it had nothing to do with the weight, only the length of the bullet.

I can only conclude that some people actually meant bullet length and not weight because a heavier bullet's OAL is different than a lighter one.

If that makes any sense at all...

 

[JohnKSa]

If the bullet is of the same style and caliber and is made of the same materials with the same construction techniques then the heavier it is the longer it will be.

It's not really accurate to say that "bullet spin is affected by weight of the bullet given a particular twist rate", bullet spin is affected by muzzle velocity and by the twist rate of the barrel. The bullet weight may affect the muzzle velocity of the bullet due to pressure limitations in a given caliber but that's another story.

The spin rate required for stabilization is based on projectile length, not projectile weight. However it's common (though not entirely accurate) to equate weight and length when discussing stabilization since most bullets are of generally similar construction.

One must be careful because that's not always the case. Bullets made entirely of copper are obviously lighter for a given length and also some VLD bullets are long for their weight due their design. Likewise Round Nose bullets (as opposed to Spitzer designs) are short for their weight.

 

[brentn]

That clears up what I had suspected, thanks!