Again, it isn't just about the bullet weight, but the bullet length as well that matters.
Plenty of folks ran the M40, M40A1, M40A3 and M40A5 out past 1000 yards just fine, which has a 1:12 twist barrel, and ran M118LR rounds, essentially Federal GMM SMK 175gr. I did reach out to a sniper instructor peer who has combat experience with the M40 rifles, who confirmed the distance and capability for me.
We also have
@FUNCTIONAL with very direct experience running the M40. Sorry to call you out but it's important. Hell I want to share more of that shot data just as a solid reference...
There's no reason why the 1:12 Lothar Walther barrels aren't extremely capable. But, the right round needs to be chosen for it.
And so this circles right back to why I made my original post sharing the shot group: the Sierra 168gr TMK round with it's improved 9° boat tail seems to work best in this barrel, which I've so far tested in 20", and I have no doubt will perform equally well in my 24". My next range day I hope to get 300 round shot groups, and later, 700 round shot groups depending on wind.
I'll share all the images and data I have on this round. For us Yankees, the Federal GMM SMK 168gr & 175gr, and the Federal LE T308T 168gr, seem to be the most effective and cost conscious round to use in these barrels.
I don't have experience with Lapua or Berger rounds in these calibers, so I leave it to others to comment on what else shoots well. I invite it as this data is important for folks like us to have.
And yes, I read every single post in this forum regarding the Arctic Warfare and AT308 looking for ballistic data of factory rounds, and found excruciatingly little.
I hope the attached data helps for context. And I have much more data that shows how the length of Hornady rounds do not stabilize. I also tried the stability factor with a Berger 185gr round without success, but I'd entertain actually shooting it to see how it performs.
thank you good sir!
