A cast bullet is hard, but it is nowhere near the hardness of copper.

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.

This has sorta left the track of my op but also brought out good points. My original quest was to find a better "why"for the small cal.,.30,8mm in my case,lack of high BC spire pointed type cast bullets or moulds. To date I've had "the tips get deformed too easy""they're too hard to get to shoot well/consistantly"and my favorite"you're an idiot if you're punching paper with TSX's". This thread has reinforced my belief that it can be done and that it will be sucessful enough for just about any caster shooter to do well.
My bullet as of now tips in at 200 grains has a .11 meplat and a calculated BC of .476 . So far hitting 1800 in any of the rifles hasn't happened due mostly ,at this point ,to lube failure. I need 1725 to get the minimum legal energy limit.

As I said, in the lower velocity ranges, a round nosed bullet can actually be more aerodynamic. I think that is at the speed of sound or below. You may be above that range, at 1700 fps.

However, at that velocity you get rainbow trajectories anyway so why do you care about bc?

You want help with this go to the cast boolits forum. They know their stuff.

Have found a great deal of info and inspiration there. However this senerio is outside of most of the guidelines.

Seeking the BCs will allow me to actually shoot quite flat ,comparitively. I have the insight to know this bullit will half the effective no hold over range. This is really more about 200 yard competency as I flat threw away my 1 shot last October.