Highest BC Bullet... ????

[LRRPF52]

Even with the fast 6mms like the Dasher, 6x47, and 6 CM, it’s hard to hear them impact on steel even at 700yds. When I’ve RO’d at matches, we’ve always had that problem of registering the hits.

In no-wind conditions, no problem. I can hear .223 68gr and up impact without much issue, as long as there isn’t wind, even out to 1000yds. But I can recall 2 days over the last 13 years here in Utah where we had those conditions, and one was actually at night when the wind had totally died, guy was confirming zero on 600yd range, impacts were very audible.

I was going to mention single-loading in the bolt gun and loading the 130gr or longer class out long to optimize the projectile relative to the shoulder neck junction.

What I found in gas guns using the same barrel length between my .260 Rem and 6.5 Grendels, I was hitting the Grendel mv from the .260 Rem at around 200yds, with the exact same bullets, magazine-fed. .260 Rem is easily supersonic to 1400yds+ in my elevations, which are similar to yours (4400-6600 at the ranges I go to, then 9000+ for elk season up in the Uintahs).

Here are some dummy cartridges I made with cutaway to show where some of the 140gr are relative to the powder column:

140gr Berger, 140gr A-MAX, 131gr .257 Ace, 6mm AR, 123gr SST standard Grendel cartridge