I don't know if this will help you but I'll throw it out there anyway.
Back in '68, I used a M52-1 for bullseye shooting.
I had a
very good source for W-W factory 148 gr. HBWC ammo by the case. It functioned 100% in my 52-1 and gave me a good source of brass to reload.
My point, back then 2.7 gr. of Bullseye was "the" 25 yd. load with a 148 gr. HBWC and 3.0 gr. was "the" 50 yd. load.
My 52-1 shot to the same POI at 50 yds. with the factory load or my reload w/3.0 gr. of Bullseye.
I used the R-P 148 gr. HBWC due to availabilty and price, I worked at a LGS at the time.