Developing 20 Tactical Loads
Posted: Thu Mar 24, 2011 12:21 pm
Sometimes it is hard to understand why one particular load just shoots tighter groups. Anyone who thinks it is easy, needs to think again. Last fall, I had a mini Mauser rebarreled to a 20 Tac. Used a PacNor barrel, 1-10 twist. The gun has shot 32 VMax into .250's but had never tried 40 VMax with Benchmark until yesterday. Started with 25 Grains of Benchmark and shot 3/4" the next load was increased two tenths and it shot a .305 outside measurement which equates to a .101 group. Next load when back to 3/4". Now the work begins to see if I can come close to duplicating that group. By the way, that is a very lightweight 22" barrel.
I have not run into tenths of a grain being so different in group size, since I developed loads for my Sako 243. Half of a grain of 4350 made for really small groups, while up and down with the powder charge, did not produce good groups. I have to get all this done and plot the trajectory before it comes time to hunt rockchucks.
I have not run into tenths of a grain being so different in group size, since I developed loads for my Sako 243. Half of a grain of 4350 made for really small groups, while up and down with the powder charge, did not produce good groups. I have to get all this done and plot the trajectory before it comes time to hunt rockchucks.