From ar15.com 150 gr HPBT Win 748 loaded to a chamber pressure of 56.4K PSI WARM load 45 gr NOT a starting load. I chose 748 as the powder as it is most like NATO powder.
26" = 2918 FPS MP= 6.6K PSI ––99.6 % powder burnt -2836 ft/lbs
24" = 2873 FPS MP= 7.4K PSI ––––––––––––––––––––––––––––2750 ft/lbs
22" = 2823 FPS MP= 8.2K PSI ––––––––––––––––––––––––––––2655 ft/lbs
20" = 2766 FPS MP= 9.2K PSI ––98.7 % powder burnt -2548 ft/lbs
18" = 2700 FPS MP= 10.5K PSI ––––––––––––––––––––––––––––2428 ft/lbs
16" = 2623 FPS MP= 12.0K PSI -97% powder burnt ––––2291 ft/lbs
14" = 2531 FPS MP= 14.0K PSI ––––––––––––––––––––––––––2133 ft/lbs
12" = 2417 FPS MP= 16.7K PSI -94% powder burnt ––1946 ft/lbs
10" = 2273 FPS MP= 20.5K PSI ––––––––––––––––––––––––––1721 ft/lbs
8.0"= 2080 FPS MP= 26.0K PSI -87% powder burnt. -1441 ft/lbs
6.0"= 1800 FPS MP= 34.1K PSI -79.4% powder burnt -1080 ft lbs