Soooo....did my first "ladder test" yesterday. I put "ladder test" in quotations because I'm quite certain that I did not follow the process to the letter, but it was still informative.
A bit of background. I started out with 30.0 grns. of LeverRevolution and 88's. It shot well enough (at around 2,950 or so), but the couple times I chronographed it, the extreme spread was terrible (I only ran 3 rounds over my chrony, thought it may be "just my cheap chrony", but a friend's magnetospeed gave the same result), around 60-65 fps for just a few rounds! I had always just picked out a load that looked good, chronied it to be sure I wasn't too hot, shot a couple groups at one or two hundred yards and started yanking the press handle. I though only benchrest guys and guys that like to pick fly crap out of pepper worried about extreme spread and standard deviation, but when I figured out that spread meant about a foot of variation at 1,000 yards, it got my attention.
First, the 88 ELDM's and RL-16. I had ran a few over my old chrony to figure out what charge range I wanted to "ladder". I may have prejudiced my own results in the process, but I didn't want to be really slow, and didn't want to push things too much. We ran a magnetospeed and shot at 300 yards. Unfortunately, circumstances didn't allow us to drive back and forth to the target, and neither of us owns a spotting scope worth a crap. So I wasn't able to number the bullet holes in the target. But, looking at the numbers, I shouldn't be hard to figure out who landed where.
Rifle specs; Bighorn Origin, 24" Bartlein 5R, Rem Varmint/Sendero contour, .080" throat, chambered by Southern Precision. KRG Bravo, Burris XTR II 5-25, 9" SAS Arbiter Suppressor. I've posted a pic of it here before.
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The round out of the group was #1. That was out of a cold bore. Everything else went into 1". Two of them into the same ragged hole. Looks like 31.6 is where I want to be.
Now the 95's and RL-16.
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The wind kicked up a bit shooting 95's, and I felt like I may have pulled a couple. But it was all still in 4" and I'm betting I know where the three in the middle came from. Gonna load a few at 30.3 and see what happens on this one.
As far as seating depth, the 88's were loaded at 2.350" OAL. The 95's at 2.310" OAL.
As I've said, I'm aware we didn't run this test exactly how it needs to be done. But I would welcome any observations or opinions.
Thanks!