Hoping to help and also explain myselfer. I do not use calculations as there are to many variables. Bullet weight and length are two different things. I try to shoot as heavy a bullet that the caliber will stabelize. This is for cast only. Jacketed is a different world. besides weight center of gravity is also important in the design chosen. My 30/30 Uberti and 30/30 wesson both 12 twist for some reason shoot these bullets sub MOA to 200 yds. they are cast from lynotype and i have quit using the gc as I found them unnecissary at the aprox 1650fps i load to. I only shoot fixed amo. never seen a need for breach seating with my chambers and brass. These bullets also work well in my 10 twist Garand with the gas port open. I also found that I could PP them to .314 and they work well in my 9 twist Arisaka. I am just trying to share information here. Love u guys even Joe
Tom

John
I told you a long time ago that my fixed will shoot as good as your breachseated. I think my chamber and brass fit as good or better than your breachseater. If we get some decent light tomorrow Ill show my 7mm/08groups can't find a 200yd 30cal tonight
Tom

Tom thank you for sharing your target, that is some very impressive performance indeed. When you get a chance I would truly enjoy looking at the other targets.

I would love to hear the steps you took to prepare your brass to able to achieve that level of accuracy. I have never pursued shooting fixed ammunition and with the success you are having it would be well worth a try.

J.Louis

John
Here is the guy you need to talk with. 
Now this statement is something I have not been able to achieve but have tried to accomplish for several years without any success. ( The first shot from a clean barrel in the group formed by the following shots ) He also states I have two Ruger #1's capable of one-half minute of angle accuracy at either 100 or 200 yards. I am talking about plain base lead bullets and fixed ammo.
 
He then goes into the brass prep required to shoot fixed of which I have no interest in doing. Caliber 30-30, 1-12 twist, alloy BHN 16, bullet NEI 190 308PB, primer Fed 210M, powder 4759, charge 16grs, lube Texaco Tarax.
This is a real feat;
Tom

Tom that fellow is Merrill Martin and he used to shoot Schuetzen matches at our club back in the 80's. Unfortunately he is no longer with us and is hanging out with the likes of Pope, Schoyen, Peterson, Dell and the other great innovators and skilled marksman.

J.Louis