I have a puzzle on my hands. I have been reloading since about 1974-75. I have run into a situation that has me baffled. I have a 6.5x55 Mauser with a 24 inch barrel. If I load loads from the manuals for the 140 grain bullet, I can come close to the velocities listed in all the manuals. However when it comes to loading lighter bullets I can not even get close. Loads that should get 2700-2800 fps will only yield 2500-2550. The loads show signs of approaching max with the primers starting to get pretty flat. The rifle has an extremly long throat and and the 140 grain Barnes X bullet is the only bullet that will reach the rifling at all and it just barely reaches. By the time I seat it to a safe depth I am 50-70 thousands off the rifling. Could that in anyones opinion be causeing the poor performance of the lighter bullets? I have had the gun for years and as long as you stay with the long 140 grainers it does a pretty fair job. How many of you have chronoghraphed 6.5 x 55 loads and what were you getting for readings? I have not as yet tried the 120 grain Barnes X bullets. Barnes bullets because of thier long bearing surface almost always yield higher velocities given the same charge and such. My 250-300 velocites jump by 200 fps just going from 100 grain Noslers to 100 grain X bullets. That is with the same powder charge.