On my last visit I shot 3 loads of 38Spl and 3 loads in a 357Mag. These were shot in 4 different handguns in each caliber.
In each case, the "book" load was the mildest and shot the biggest (worst) group. As the loads got hotter (.2gr increments in 38, 0.3gr increments in 357) the groups got better. The hottest group was the best.
This left me with a clear task on my next test. I had to repeat the test in 8 different guns, to see if the load had some general value and I also had to test one more increment hotter, to see if the trend of tighter groups continued.
This batch of 38s had the same best load as the last batch, and the one increment hotter was still good, but not quite as good, so I have a result that is valid in 8 different 38Spl revolvers.
In 357, these 4 guns gave the same result as last time. Mildest load was the worst and the same hot load was best. But the one step hotter was even better, but not a lot better.
Each time I test I try to have a good variety of makes of guns. In this today's batch of 357's, there was a Colt, a Taurus, a Uberti , A Smith and a Ruger. I find it remarkable that each showed the same bell curve of groups size vs powder charge.
In 357, I ran 148WC over 3.5 to 4.4gr of N320. Velocity was 825 for the mild load and 955 for the hottest (best) load.
In 38Spl, the best load was 3.6 of N320 at 855 fps.
I put up cardboard sheets of targets. Each target is numbered.
And I keep notes at the bench of what load was shot on each target.
The 357's today:
In each case, the "book" load was the mildest and shot the biggest (worst) group. As the loads got hotter (.2gr increments in 38, 0.3gr increments in 357) the groups got better. The hottest group was the best.
This left me with a clear task on my next test. I had to repeat the test in 8 different guns, to see if the load had some general value and I also had to test one more increment hotter, to see if the trend of tighter groups continued.
This batch of 38s had the same best load as the last batch, and the one increment hotter was still good, but not quite as good, so I have a result that is valid in 8 different 38Spl revolvers.
In 357, these 4 guns gave the same result as last time. Mildest load was the worst and the same hot load was best. But the one step hotter was even better, but not a lot better.
Each time I test I try to have a good variety of makes of guns. In this today's batch of 357's, there was a Colt, a Taurus, a Uberti , A Smith and a Ruger. I find it remarkable that each showed the same bell curve of groups size vs powder charge.
In 357, I ran 148WC over 3.5 to 4.4gr of N320. Velocity was 825 for the mild load and 955 for the hottest (best) load.
In 38Spl, the best load was 3.6 of N320 at 855 fps.
I put up cardboard sheets of targets. Each target is numbered.
And I keep notes at the bench of what load was shot on each target.
The 357's today:
