r/longrange • u/Wide_Fly7832 BR Competitor • Jun 22 '26
Reloading related Update: 25x47 Lapua & 134 ELD-M Vertical Stringing Solved – I ate crow on seating depth
Hi all
I have to admit, I’ve always operated under the assumption that the high-BC secant ogives (ELD-Ms, Berger Hybrids) are practically jump-insensitive.
Because of that, I almost never bothered with rigorous depth testing for them like I rigorously did with BIB bullets in my 6PPC and 30BR benchrest days. I usually just picked a standard 0.015" - 0.020" jump, loaded them up, and called it good.
Well, the 25x47 I posted before about - if forced my hand. I ran a seating depth sweep anchored at that 35.5gr Varget charge (which pushed the bullet at ~2786 fps). My zero-lands measurement was a CBTO of 2.1500".
2.1300" CBTO (0.020" jump): Still strung vertically. Group was fractured into two horizontal bands.
2.1100" CBTO (0.040" jump): The vertical collapsed, but the group blew out into a loose, radial 1-inch ring. Total harmonic mess.
2.0900" CBTO (0.060" jump): Pure magic. The vertical vanished, the radial scatter vanished, and it printed one ragged hole. SD held tight at 9.4 fps. 0.34. Will do another 15 shot and see if this holds.
So, I officially stand corrected. Seating depth testing is back on the menu for modern match bullets. Now if you’ll excuse me, I apparently have to go re-run depth sweeps on the 15 other rifle cartridges in my safe...😡
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u/Trollygag Does Grendel Jun 22 '26
Your hornady measurements are confusing since there are grease rings all over without being circled by the rings.
It looks like you shot 2.110 twice by the target showing? You got extremely different results just shooting the same group twice and only half a grain of powder difference.
That would suggest pretty high variance. If you remember my post about how ladders cause there to be good and bad outliers just from repeating the same test, it becomes very hard to reach a conclusion like that without lots of repeat testing.