I opted to try using the Ladder Test for this next stage of the process.
Primer — CCI #41
Brass — Remington used (2x fired at this point). 1.750″ trim length, flash holes deburred, primer pockets uniformed
Bullet — Barnes TSX .224″ 62 grain
COAL — 2.250″ (taken from Barnes #4 manual)
Powder — Varget
The big change here is using Varget. I have 30 rounds loaded. There are 10 “steps” of powder, from 23.7 grains up to 25.5 grains in 0.2 grain increments. There are 3 rounds of each charge weight.
I went to the local indoor range to try things out, because 1. it was nearby, 2. I can shoot at 100 yards and not have to worry about wind and other conditions; weather right now isn’t that ideal. Downside is I can’t chronograph things, but I’m not considering that vital at this point. Once I figure where things look accurate enough then I’ll chrono.
I don’t know what to make of the results.
If I look at the pictures from the ladder article, what I should see is the greater the charge weight, thus the more velocity, thus the higher (vertically) the impact should be on the paper; that the holes in the paper should “climb” as I go up in charge weight. That didn’t exactly happen. Shots from the lightest charge weight ended up shooting the highest.
Furthermore, I was unsure about shooting only 3 rounds because inevitably you’ll get 2 good shots and 1 that screws things up, and I certainly got that; two would be close, then one would be off somewhere else. I read that statistically 7 is the best number to use as it best balances giving enough worthwhile statistical data but also keeps the amount of components used to a minimum. I just have to be mindful of my component consumption, plus the ladder test article said to go with 3, so that’s what I did.
If I look at where the shots clustered….
25.5 grains produced a 3-shot 1/2″ vertical group. Note that for this test vertical is what we care about, but even with that the 25.5 grain group was the overall tightest with the 3 shots literally stacked atop each other and touching. I can cover the group with a nickel.
As I read online, I see others shooting similar situations (62 grain TSX, Varget, and even shooting out of 1:9 twist AR’s), that they’ll have good results with 25.0 grains. I’ve also read of good success using 26.4 grains which generated almost 2900 fps from a 16″ barrel, and another using 27.5 grains out of a Bushmaster SS varmint (getting 3400 fps). But note 25.5 grains is the listed max in the Barnes manual and those last 2 greatly exceed that. Of course, they all were shooting out of a 5.56 chambered rifle, so they can handle the additional pressure.
That said, as I look at the vertical window, 25.5 certainly gave me the best overall performance. 25.1 grains looks to also have promise. Anything much below that seems to not provide that great of results. But this appears to be consistent with what I’ve been told, that Varget tends to come into its own when pushed closer to the max. One possible reason? When you get up in charge weight it starts to cause a compressed load, which apparently helps Varget.
What I think I may do at this point is start at 25.1 and load in 0.1 grain increments up to 25.5 (I don’t feel like going past max, if I don’t have to). But this time, I’ll load 5 rounds or maybe 7 depending on my component count. The point being to try to get a bit more statistical spread than what 3 rounds can give me. See how that goes.
In related news, the Varget does feel different from TAC. There’s not a massive difference, but the TAC feels a bit snappier than the Varget. Or it could just be how I was feeling today.