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.

I' ve had many a time when I couldn' t reach the stated velocities published in a handbook. The good news is that you' re being a smart handloader and stopping because of the pressure signs and not the published data.

There have been a few times when I went several grains above max.....especially with a .257 Roberts and a .300 H&H.

I sure hope someone posts with an explanation of these things.....but from my perspective " stuff happens" and we may never know why.......but accept that you have done your job well.

Not every question has an answer.

I would load up the 120 gr. Barnes X bullets, and see what happens. Keep us informed. Good luck.

I will get a box of the Barnes X bullets and give them a try. I quess your right, sometimes there is no answer and I know thats what makes guns each onto thier own. I sometimes run into a wall and hate to drive around it. The gun has killed deer like a bolt of lightning for years but it won,t behave like it should. I was getting rather low velocities from the new Roberts until I tried the 100 grain X bullets. However just adding one grain of powder and changing from a standard primer to a Mag primer brought the Nosler ballistic tip from an average of 2649 up to 2791. I am still half a grain below max in the book. Thats close enough for me. I am very reluctant to go above the listed Max loads. The Barnes 140 grain X bullet reached 2688 in the 6.5x55 with the Max load of IMR 4350 with a max variation of just 12 fps. I will stay with that load. Never could get past 2600 fps with the Hornady 140 which I have used it it all along. This is really the first of many rifles that I have had which will shoot heavy bullets faster than light ones. It don,t make sense but like you say STUFF HAPPENS. Thanks .

I had an experience very similar to yours when trying to achieve some high-velocity performances with 120 grain bullets in a couple of Ruger 7X57mm rifles. One was a M77, the other a No. 1A. I was using WW 760 powder, with which I was able to achieve 3000 FPS with 140-grain bullets, so I assumed 3100 would be possible with the 120 grain. WRONG! The best I was able to achieve with acceptable pressures was around 3020! In fact, I passed the " crossover point" , where pressure was continuing to rise, but velocity actually dropped a little!

I ran into the cross over point a few time with a Winchester 7MM Mag with 140 grain bullets. I think we were using H450. I also have run into points with slow burning powder where velocities rise to a certain point then began to fall off. I had a 280 Remington at the time as well. I could acheive higher velocity with the 280 than I could the 7 mag with the same bullet. Sometimes things just don,t work. I will keep trying but the most important thing as someone above said Safty first this may just be one of those rare cases where I am stuck with one bullet bullet weight with that rifle. It is a 69.00 dollar rifle when I got it. I put another 100.00 in it in the form of a timney trigger and some machine work to change the bolt handle and drill and tap for scope. My cousin shot an elk and a moose with it and I have shot about 25 deer with it. All with the 140 grain Hornady bullet. The moose was shot with a hornady 160 grain round nose. I would have to find my old chronograph book to see what we had for velocity on that bullet I keep a close record of all loads chronograghed over the years and the data on the loads. Its a valuable reference book. I filled one book and retirted it but its still here somewhere. I have probably got readings on several hundred rifles and pistols. I used to go to the range every Saturday and everyone who had loads to test and didn,t have a chronograph would misteriously show up. My first one used those old paper screens which were not cheap or easy to get. The 17 remingtons used to shoot between the little lines on the screen and fail on one end or the other. Thanks.