Re: 338 SIN Testing
Went out this morning to do some more testing. It seems with the lighter bullets this rifle likes the faster burning powders. I tried some new loads for the 185 grain Barnes ttsx. H-414 was the clear winner over several powders. 89 grains with a fed 215 match primer averaged 3515 fps and was by far the best load with accuracy, velocity, and velocity spread. I have had extremely good performance out of this powder shooting light bullets in the 338 winchester, 338-300 wsm and the 300 wsm along with a few others.
I shot a 3 shot 100 yard group for zero and all three shots were touching. I carried it out to 800 yards and shot a 8 3/8" group. The BC on this bullet still amazes me. Last year I did quite a bit of shooting with this bullet in my 338 winchester and had to plug in bc's around .5 for it to match my drops. I know this bullet should not have this high of a bc but it did the same thing today. Later I am shooting it over two calibrated chrono's and get it down instead of doing drop tests. I just haven't had time to do that yet.
The rifle is a 24" barrel 1-10 twist. I also shot some 225 CE bullets with several different powders. 93 grains of Wichester WMR averaged 3121 fps, 96 grains of Magpro averaged 3114 fps, 86 grains of I-4831 averaged 3153 fps and 85 grains of RE-19 averaged 3160 fps. All of these loads are max in this rifle. This rifle shoots best with max loads. Velocity spreads got smaller and accuracy got better as the powder got faster. They improved exactly with the powder burn rates. So in my rifle the faster the powder the better to RE-19 with this bullet. I may try something faster later like H-414 that did outstanding with the 185 grain bullet.
The best accuracy and least velocity spread (8 fps) was with 85 grains RE-19. The 100 yard group was all touching and the 800 yard group was 7 1/4".
What I am finding is this cartridge performs very well with faster burning powders than what you would normaly see in a 338 cartridge with this level of performance. This is due to the efficient design of the cartridge similar to the wsm cartridges. Because of utilizing faster burning powders this cartridge does great in short barrels which is what I was looking for in a lightweight backpack style rifle. A 225 grain .65 or so bc going 3160 fps out of a 24" barrel lightweight rifle that weighs a little over six pounds is pretty amazing.
Predictions are difficult, especially when they involve the future