Flatsguide (bone fishing guide?) - your the prolate will be an excellent choice in your rifle, all the way to 1000 yds. Your bullet's length will be aoubt 1.46" or so. This mould from BACO will get the job done every time
http://www.buffaloarms.com/Bullet_Mo...px?TERM=Jim443. Load about 82 grs of Swiss 1.5fg and a 0.06" wad then compress to 0.1" below the case mouth (do not seat deeper than 0.1") and you are good to go to 1000.
If the bullets in your cases are too floppy after you set the bullet in them, you might try taking the depriming stem out of your FL sizing die and sizing the neck of the case. This is effectively a taper crimp and you should be able to get just enough crimp to barely hold on the bullet.
Bruce, My noses are not 2 calibers long - that would be 0.9"! I don't know anyone shooting noses that long. In fact, they are usually around 0.74" - or roughly 1/2 the length of most of my bullets.
This is my long range bullet. It has the 4:1:1 nose of about 0.74" but it is a little longer in the shank to be 1.51" overall and weighing 537 grs. However, this bullet it TOO LONG for an 18 twist. I use a 16 twist with this bullet.
The guy that made this mould only does them from time to time. Brooks has made a 1.46" long version for my 18 twist silhouette rifle. However, the BACO mould linked to above, is the easy way to fly. It is effectively the same bullet.