Well, Ben B. predicted what I would find. And Dellet articulated why…
Dellet’s suggestion to run a more granular ladder series struck me as on point. And so that’s what I did. I loaded a second ladder, in 0.1 gr. increments, from 19.6 to 20.2 gr.
With seven individual loads in the series, I dropped the round count in each to three shots in order to keep the total shot count reasonable.
As with the original series, all charges were individually weighed on an RCBS Chargemaster 1500. COAL was 2.250. The test rifle was a Ruger American Ranch Rifle (RARR) with a 16.12” barrel. And the range was 50 yards. Chronograph readings were made with a LabRadar. Ammunition – though not the weather itself – was approximately 70 degrees at the time it was fired.
As before, the first group was of the Barnes factory load. Because the group from that factory load was so abysmal during the first series, I put five fouling shots – versus two in the original series - down the barrel before going to paper. Yes, I know it’s de rigueur these days not to clean one’s guns between shooting sessions – to “let the gun tell you when it needs cleaning.” I confess, though, to being old school in lots of things, and this is one of them. My guns all get put away with freshly cleaned, freshly oiled bores.
That said, some guns need a few more rounds before they settle in, therefore the five foulers.
One other minor tidbit regarding the factory load… I found it interesting that the three previous record groups all came in at just over 2300 fps, notwithstanding their poor extreme spread and standard deviation numbers. This time the muzzle velocity came in a touch higher. Thinking about it… I went and pulled the boxes. Sure enough, the first three groups were all from one lot; this last group was from a different lot.
There’s a seductive compulsion to take that 3-shot group we just shot and compare it to the 5-shot effort a week ago. You have to resist that. They’re apples and oranges. Group size and extreme spread never shrink with more rounds downrange. They only ever grow.
But you can still see patterns. In this case I’m actually more interested in the vertical dispersion from group to group than I am in group size. And because of that I’m already rueing a bit my early decision to shoot at 50 yards rather than 100. The information is still there at the shorter distance, but it’s a little harder to see.
But it all comes together back inside, the rifles (I put a few rounds through my No. 1 in .45-70, as well) cleaned and put away, sitting in the easy chair in front of the wood stove, with the laptop and the chrono data.
We’re never done with the shooting, of course. The journey continues, on and on. There will be more testing, more experimenting.
But in the meantime, 20.0 grains of Win 296 looks like a nice place to start. Or to end.
Merry Christmas.