I shot a couple of my rifles through the chronograph this past weekend, and got some surprising results. My 7-08 shot speeds comparable to the listed speeds in the manual, but my 7mmRM shot WAY slow.
Here's an example: Shooting a 160 gr Accubond loaded with RL-22 to the the max level listed in the Nosler manual (I can't recall the exact number an don't have my notes here right now), the 7mmRM shot about 2800 fps, which is more than 300fps slower than shown in the Nosler manual. My Ruger M77 MKII has a 24" barrel, the same length Nosler used.
Even loaded a grain or two above the max listed load, I still wasn't even close to listed speeds.
The same was true for RL-19, the other powder I tested. All loads of both powders were 300fps slower than what is listed in all the manuals I referenced.
I don't think my chronograph was off since the 7-08 was shooting about 2850fps with 140 grain Accubonds with various powders, which is right in the correct range for a 22" barrel.
What could cause such a large difference?
I should mention that even the loads that were a grain or two above the max load listed in the Nosler manual showed absolutely no signs of excess pressure. No primer issues, no base expansion or bright spots, no sticky bolt lift. Should I just work up to higher load levels? If so, what sorts of things would cause this rifle to require more powder to get the same pressures and velocities?