Over the last 20 years of shooting my 308 Norma mag I only ever used 75gr Norma MRP with a 180gr bullet. I actually pulled a Norma factory bullet apart and weighed the powder, it was 1gr of Norma MRP more than any load manual available at that time.

When I shoot Norma 180 gr. factory loads in mine, I have to pry the bolt open. They were going just over 3200 f/s over a chrono. I tore the rest of them down and loaded 70 gr. of H4831 and a 180 Hornady BTSP for 2953 f/s. I wonder what the problem is? Tight chamber, bore? It is a factory rifle. (Firearms International) built on an FN mauser action. Rojelio

My average velocities with the 180gr bullets and 75grs Norma MRP was 3060fps with a 26" barrel.
Cam

Range report.

Velocities were down today. 75grs AR2213SC behind 180gr Hornady SPBT gave an average of 10 shots of only 3,086 fps (previously these chronoed at 3,105 fps). Today was cold (for Brisbane this time of the year) and windy whereas on the previous occasion it was 30c +. Perhaps this explains the difference.

Going up to 76 grs (3 grs over the ADI maximum) in 0.2 grs increments gave the following:

75.2grs 3,119 fps
75.4grs 3,124 fps
75.6grs 3,132 fps
75.8grs 3,138 fps
76.0grs 3,153 fps

The top load is defnitely "hot" but didn't look any hotter that the 75gr load. By the way it shot a nice 3 shot group well under the inch (.705") for such a windy day. I don't think this looad would be good in the tropics (I'll load back to the 75 grs load for that) but may be just the things for a Sambar in Victoria in winter.

Ran the load through the PointBlank ballistics software when I got home and it gives the following details:

100yds +3.23" 2,944fps 3,463flb
200yds +3.93" 2,744fps 3,009flb
300yds 0.0 2,553fps 2,605flb
400yds -9.19" 2,370fps 2,244flb
500yds -24.73" 2,194fps 1,925flb

Should be a real flat shooting hard hitter.

Cheers,
Magnum

Hi: I shoot the .308 Norma Magnum in a 1956 Sako "High Power" Rifle (before Sako built their own action, they used the Belgium FN Mauser Action)...anyway I used the "A-Square"
Reloading Manual of 77 gr. of R22. And use 77 gr. of H4831
SC to get 3115 fps with the 180 gr. bullet. Both powders work about the same for me...I don't have any extraction or
pressure problems...
The "Experts" claim Norma MRP=Reloader22, same powder by same manufacturer...except MRP is graded better so has more consistency...that info is on this site somewhere.
Best Regards, Tom