I was poking you. You learned lots already, I was just highlighting something about static fit that most people have wrong and keeps them from doing what you're doing.
Notice your bullets arced straight in? No whoop-de-doos, no corkscrewing, just a nice, true arc (and trailing Moly smoke the whole way). That means you have a balanced bullet coming out of the muzzle. But how could that be? The bullet has room to get all kinds of crooked due to not "fitting" the throat like a glove or having a long, perfectly fitted, bore-riding nose to keep it straight. The answer is you gave it some room and the right shape combination between nose, body, and throat to get all kinds of straight. The rest of the equation is the right alloy to help the bullet glide into place, and an appropriate powder to give just the right push to it. Personally, I would have tried a little tougher bullet and a little faster powder, not having had the luck you're having with 4831, but it just goes to show there are plenty of different combinations that work well at HV....if.....
...you choose the right bullet for the gun, right alloy for the velocity, and right powder for the alloy. There is a dynamic you have to achieve to get the bullet straight into the bore at HV. I call that dynamic 'balance'. You have to balance alloy and powder and have a bullet that fits the right way for the job you are asking it to do. The bullet is a plastic, living thing as it transitions from the case neck into the bore, and if you don't water it right, it dies. The rest is basic handloading skills, tuning to the barrel harmonics, and a few other details, but the basic lesson of learning what that bullet shape/alloy constitution/powder burn curve balance is and how to achieve it is the whole secret to HV cast shooting.