I finally got to borrow a chrony and made the most of it- here are the results of testing the recipes listed here on an 85 degree summer day. Test results are the average of 3 shots and were fired out of a 16″ barrel- so velocities are higher than what you could expect from a shorter barrel.
I also noticed something interesting while testing: the PMAG30 doesn't hold open when empty but the USGI and Promag mags do- even with subsonic loads.
- 178gr Amax 1089 fps
- 220gr HPBT (SMK) (using A1680) 1077 fps
- 220gr HPBT (SMK) using LilGun 1093 fps
- 235gr cast softpoint1083.5 fps
- 150gr FMJBT 1877.5 fps