I highly recommend using a chronograph when reloading. Flying by the seat of your pants really sucks compared to having data. You don\’t have to spend a fortune. A decent optical chrono works fine and provides valuable information. They cost $150ish these days. I consider it a crucial piece of equipment.

There are multiple factors that will affect velocity even if everything is assembled the same. Moisture content of your powder is a big one. Temperature is another. Plus, you have varying chamber dimensions, throat lengths and angles, bore diameters, case capacities, and so on.

FWIW, though your results will certainly vary, with Autocomp I got:

CZ-75 4.7\” barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070\”
4.9 Autocomp
Temp 77 F
5 rounds avg 1089 FPS, ES 28

CZ-75 4.7\” barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070\”
5.1 Autocomp
Temp 71 F
5 rounds avg 1118 FPS, ES 30

S&W Shield Plus 3.1\” barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070\”
4.9 Autocomp
Temp 77 F
5 rounds avg 984 FPS, ES 32

S&W Shield Plus 3.1\” barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070\”
5.1 Autocomp
Temp 72F
5 rounds avg 1022 FPS, ES 26

8 rounds of factory standard pressure Federal 124 HST from the same Shield Plus fired at higher elevation at 73 F averaged 1004 FPS with an ES of 17.