Yo See-See,

I wouldn't give up on the BT's quite yet.

Instead of commenting on the Pro's & Con's of the various bullet shapes I'm gonna take another tack altogether.

Keep loading whatever you want in your 257R but give the Lyman VLD inside Chamfering Tool a try. The coupla bucks spent just to compare and the much increased angle as opposed to the slight angle of the vast majority of Chamfering Tools available makes a noticable difference when seating bullets; especially the Flat Based Berger Match bullets. Boattails seem to slip in the case almost without any effort at all.

Back when I started reloading in 1948, all I had to load on was my Step Dad's Belding and Mull BM2 loading tool. He had it mounted on the inside of the lid of an old treadle sewing machine table, and we did everything in the horizontal position. In order to keep the powder from falling out of the case mouth when seating bullets, we used Industrial Products Company Colloidal Graphite wads. The colloidal graphite came in thin sheets about .020, or .030 thick to press in the case mouth. After using a sheet it looked like Swiss cheese with all of the holes left in it.
That kept the powder in the case till the bullet was seated. However, when shooting a bunch of rounds through the barrel, the emulsified graphite would ooze out the muzzle of the barrel, and in a way was kind of like the molly treatment with bullets today. It kept the barrels lubricated. I always thought that was kind of neat, as a kid...
Sure was happy when I bought the C-H "H" press so I didn't have to do the graphite wad trick any longer. The stuff got all over everything, and your hands came out black with the graphite goo..

Don