Junior Program Load Development
As we move forward toward a summer of Junior shooting, we are working to overcome the problems of not being to able to get the “good stuff” to load ammunition for the program.
As I’ve noted earlier, we have been able to find components, but they are not what are generally considered for “Match Loads”. We have Russian primers, not CCI Match, Remington 7 1/2 Bench rests or even WSR, but they are generally considered to be pretty good. We are using military cases; LC, WCC and a few TW. Most have several reloadings behind them, so we will need to watch for neck splits.
Our bullets are Sierra 69-grain Match Kings. For some reason they come up as available at suppliers and when I get an email notification, I grab some. Natchez Shooting supply had 100-quantity boxes one day. The next day they were gone but they had 500-piece boxes. You bet your hat I grabbed some both days – we are pretty good to go on bullets.
The biggest unknown has been propellant. I was able to buy two 8-pound jugs of WC-842 surplus pull-down powder in a parking lot at a convenience store way out in the country south of Warsaw. It wasn’t a midnight drug sale, but it did feel weird! Surplus powder is a big unknown, it is a mix of powder lots from surplus ammunition that has to be demilitarized and cannot be sold as complete rounds. It has to be characterized one jug at a time.
Just after New Year’s Day, Aaron Kohler and I did pressure tests to see just what this powder looked like. We started at 20 grains which chronographed as way too slow and went up to a load that was a bit too hot – we pierced the primer. But, we found that the sweet spot was between about 22.4 grains and 23.8 grains.
The next step was an accuracy test to find if there was a real sweet spot and if our components were compatible when we put them together. I loaded six rounds at 0.2 grain increments from 22.4 to 23.8 grains. The test protocol would be that Mike Grannis would shoot half from a match gun and I would shoot the others from my stubby barreled service rifle. We would shoot on the Silver Mountain electronic targets and use the circle tool to record group size – easy/peezy. We chronographed the service rifle for muzzle velocity and used the Silver Mountain system to get target velocity for both rifles.
The quick answer – we have components to make some pretty good loads. Mike was shooting his Match rifle with a 20X scope and I was shooting the Senior Chief at 4X, so it would be expected that Mike would shoot tighter groups that I would, he actually shot groups about half the diameter I shot. But, in both cases we found that in the short barreled service rifle and the long barreled match rifle, groups were as tight as either one of us thought we were able to shoot.
The picture shows the 100-yard target we were shooting with a Shoot-n-See center. Mike’s aim point was at 12 o’clock on the center and I was hitting at 6 o’clock on the edge of the black. We chewed it up pretty well for a couple of old guys with runny noses and watery eyes on a chilly, breezy afternoon.
I am attaching a graph with a lot of data on it – look at it and I think you can see the same sweet spot I see. Once we get our new rifles I am going to run one more test at 22.8, 23.0 and 23.2 grains of powder for a load. I suspect that about a 23.0 grain load is going to give us the capability to shoot about half-inch groups off the bench. That makes the shooter the limiting factor – exactly what we are looking for.
Now, we wait for rifles!