Author: Macd
Subject: TrailBoss powder loads for 180g cast bullets
Posted: February 06 2018 at 7:05pm
So I finally got out to the range today. Results with Trail Boss at both 10.5 and 15 were disappointing. Velocities were very consistent with 10.5 running from 1143 fps to 1147. At 15 grains they ran from 1219 to 1237. This is significantly below predicted. It was hovering around freezing and TB is temperature sensitive. Accuracy at 50 meters was 2 to 2.5 inch groups. I then moved up to Varget at mid jacketed levels 38 - 38.5 grains. Velocity spread was over 100 fps for each loading and accuracy about the same as the Trail Boss. I had some 39 grain loads with me but the top 38.5 shot was just over 2200 fps. My experience is that definitely is pushing the envelope for gas checked cast I suspected the bullet was the problem but when I got home and was cleaning the rifle I discovered the butt stock screw has loosened so I am not so sure now. I also learned that I need to move to a longer eye relief scope and add some length to the length of pull. Got some nasty abrasions on my nose from the scope cover when shooting semi-prone.
The day wasn't a complete loss however. I finished load development for my 6.6x55 Swedish M96 Mauser. It put five 139 grain PRVI FMJBT bullets into a nickle sized cloverleaf, again at 50 meters. That is off of a shooting bag, 2x7x40 long eye relief scope. Powder was 43.2 grains of HV100. My previous best was with 43.0 so that little bit of extra powder found the sweet spot. Highest velocity was 2653 fps. Incredible for a military rifle made in 1905.
Subject: TrailBoss powder loads for 180g cast bullets
Posted: February 06 2018 at 7:05pm
So I finally got out to the range today. Results with Trail Boss at both 10.5 and 15 were disappointing. Velocities were very consistent with 10.5 running from 1143 fps to 1147. At 15 grains they ran from 1219 to 1237. This is significantly below predicted. It was hovering around freezing and TB is temperature sensitive. Accuracy at 50 meters was 2 to 2.5 inch groups. I then moved up to Varget at mid jacketed levels 38 - 38.5 grains. Velocity spread was over 100 fps for each loading and accuracy about the same as the Trail Boss. I had some 39 grain loads with me but the top 38.5 shot was just over 2200 fps. My experience is that definitely is pushing the envelope for gas checked cast I suspected the bullet was the problem but when I got home and was cleaning the rifle I discovered the butt stock screw has loosened so I am not so sure now. I also learned that I need to move to a longer eye relief scope and add some length to the length of pull. Got some nasty abrasions on my nose from the scope cover when shooting semi-prone.
The day wasn't a complete loss however. I finished load development for my 6.6x55 Swedish M96 Mauser. It put five 139 grain PRVI FMJBT bullets into a nickle sized cloverleaf, again at 50 meters. That is off of a shooting bag, 2x7x40 long eye relief scope. Powder was 43.2 grains of HV100. My previous best was with 43.0 so that little bit of extra powder found the sweet spot. Highest velocity was 2653 fps. Incredible for a military rifle made in 1905.
