.300 Dakota, I had not really considered this, that it might not be superformance that is finicky but ball powder in general. The only other ball powder I've used is win 760 and come to think of it that never really pleased me either. Very interesting. I do prefer a full case of any powder, even very lightly compressed. The combo I'm considering trying it in again is a .270 with 140 trophy bonded tips. They are long bullets. Barnes lists superformance as the fastest powder I think in 270 with 140 tsx. As the tbt is a grooved solid shank pill I figured they'd be similar.
TBTs ARE quite similar to Barnes as far as handloading. You'll find out quickly that your gun either loves them or hates them. They are also coated, which helps reduce pressure and fouling, while increasing velocity. The coating is nickel, not stuff that clogs the bore. Accuracy is not affected in subsequent groups with conventional bullets. This is the old Bear Claw with grooves, a coating, and cool translucent orange tips to help initiation of expansion. These were the best killers ever designed, and are slated to make a come back, I've read.
I think Superformance is ideal for the 270, or perhaps the converse is true: The 270 is perfect for Superformance. The only other cartridge I could think of that might be better suited is the .280 Rem. If you experiment a little, I'm confident you can find a bullet/brass/primer combo that gives great accuracy and even better velocity.
That's a consideration many don't consider. Changing brass OR primers will give radically different accuracy results, holding charge, bullet, and seating depth constant. You don't want to do that near max charges, however. One can spot trends, such as heavier brass associated with higher pressure, but differences in alloy, rather than thicker walls, COULD be responsible for heavier weights. And as a rule, Winchester primers are the hottest. I don't use them. I did fairly recently just to see if I could use some up. I obtained a really good group with Reloader 23 in the 25-06 with blistering speed (over 3300 fps with 115 grain bullet), but the bolt handle was tight and ejector marks were prominent. I changed from the WLRM Winchester primer to a Federal 215 Gold Medal Match primer (yes, a magnum primer in 25-06- gives much better consistency in ignition and burn, and uses less powder) and got velocities of 3256 fps with more consistent velocities and a sub-1/2 MOA group and NO pressure! That's my current and for always hunting load in the ultralight Barrett Fieldcraft. I would not recommend making this arbitrary switch of primers at these levels of charge, once again. I am very familiar with the lot of Federal primers I used, and the rifle, and Reloader 23. Otherwise I wouldn't have tried it either. Always reduce when changing components.
