Every place I ever shot bunker allowed me to use trap loads. I have always just used 3dram 1 1/8 oz of 7.5's. I have used some one ounce also but never did try the actual bunker load. I always figured I needed all the extra I could get but never went for the speed of over 1200 fps.
If your loading on a Mec they don't make a 24 gram bar unless they just brought one out. Just load 7/8 oz OR you can use some HVAC aluminum tape and put some in the shot hole with trial and error, till you get the right weight drop. 24 gram loads are 370.4 grains, 7/8 oz equals 382.8 grains. Gary