Originally Posted by
harter66
So my 3 bullets don't care how fast they go nor what the twist rate is as long as the lands get a bite and the bullit gets out of the bbl with enough spin to get stable?
Shape has no real bearing on flight untill way after a small caliber
cast bullet is done flying.
So if the bullet length jives with twist rate and shape doesn't matter an "X"(TSX,GMX)shaped bullet gaschecked or plain based fitted properly with old fashioned powders ,as opposed to modern, should deliver equal TO target performance to the cup and core or copper cousins of the same BC and SD ? Please note to target not target performance.
All three matter. Shape matters. Sleeker designs cut through the air better. The problem is different shapes are better for different velocities. A relatively blunt roundnose .22 lr is better for the velocities typical of a .22. A long sleek Amax is better for high velocity. Two bullets of the same size and shape but of different weight have the same air resistance.
That is why weight matters. The heavier bullet will hold velocity longer for what should be obvious reasons.
Twist matters a little bit, but not in this case. The length of the bullet and to a small extent the velocity determines the twist needed to stabilize it. Three bullets of the same shape and size but different weight will all require the same twist. The light bullet may destabilize first but that is kinda irrelevant.
There are way too many variables to tell you what would happen in your case. The light bullet would have the fastest muzzle velocity, but the powder wouldn't burn as well if the same powder charge was used. It would shed the most velocity on the way to the target and the wind drift would be the highest.
The heavy bullet would use the powder most efficiently, and have the lowest muzzle velocity. Depending on how far the target is, it could have the most drop or the least.