Richard.
The data base I have in my ballistics program is quite extensive, but I don't know how old it is. Bullet makers constantly experiment with different alloys, boat tails and ogives which changes the length. Even in the same box they can vary as much as five thou.
The solid copper Barnes bullets are very dimensional consistent and are in the match grade category.
By using only bullets with flat tails, bullets are generally more accurate than boat tails. Besides boat tails are not required for any shooting under 500yds. Flat tails are also easier on barrels and throats.
The only BT bullet I use is the Barnes TSX because of its outstanding performance. It has become my dedicated 25cal hunting bullet. I tested them today in the 257 Roberts and I am very pleased with the accuracy, little more tweaking is needed with the charge.
My ballistics program indicated the TSX bullets might only be marginal stabilized. But that is not the case. At 3150 ft MV they work just fine.
The discrepancy can come from various lack of input such as the center of gravity and the center of pressure that can't be determined by ordinary means, nor is the exact specific gravity available.
I found out that this bullet was still stable at just over 3000 ft producing a 1" group, when calulations predicted margional stabilization at 3190ft using 125% gyroscopic stability. This factor is plenty for ordinary hunting ranges. Nothing like shooting to find out if they are stable or not.
