I tried them with Ramshot Tac, couldn't get them to shoot well and gave up on it. I was looking to use it as a gas gun for PRS matches but built a bolt gun instead so I didn't put too much time into it. Sierra lists the highest velocities with Tac and a couple other powders I haven't ever seen.
I'd really question whether ammo is almost the same. I'm assuming you're not reloading. In a quick search, the only 6mm ARC I could find in stock is $45/20 rd box, so over $2/rd, probably over $3/rd after tax and shipping. Now 5.56 is really scarce, but you can find some 77 gr match loads for...
Just seems overpriced to me relative to better options if you're set on AR-10's, but if that's what you're into that's cool. There's one for sale in the PX.
Otherwise, do some searches and reading here:
https://www.snipershide.com/shooting/threads/nemo-arms-308-rifle.168310/post-2949443...
https://www.larue.com/products/16-inch-larue-tactical-predatar-7-62/#panel2
Edit: The PredatOBR has a heavier barrel and that would be my pick, the website doesn't list a weight but I think it's 8.2 lbs. It's supposed to be insanely accurate.
How long you can hold sights on target is mostly a function of your position and the support for it. The PRS guys mostly practice building positions with their bags and bipods for this reason. If you're exclusively worried about offhand shots then that's going to be at least as much about your...
6mm BR is great at 600. Example here I'd you haven't seen it:
https://www.accurateshooter.com/guns-of-week/gunweek063/
From what I understand, 300 m people often use even smaller cartridges like 6mm PPC, so if that's the majority of your shooting it could be also used at 600. Good luck!
I'm a newer reloader (3 years) and admitted when I posted my velocity chart that I may have missed pressure signs. In the interest of getting more data out and in front of people to likely know more than me, here are the fired cases using 31.5 gr Varget (left two) and 31.7 gr N140 (right) that...
A 700 build would be fine (I'd look at NSS). But I'll just throw out that for about $1500 you could get a used Tikka Tac A1 and end up in about the same spot, they pop up in the classifieds here fairly frequently. The action and barrel are identical to the CTR, but the trigger is a two stage.
Yep. 6 BRA and 105 Hybrids from a 26" barrel, 1x fired Lapua brass, and 69 deg F. Using BR4 primers so again, work up slowly (and I may have missed pressure signs at the upper loads). I ended up at 31.5 gr for both.
Varget and N140 have worked great with 105 hybrids for me, and had identical velocities. The Varget was more temperature sensitive in what I tested, which surprised me, and I've heard N140 is way cleaner.
There are quite a few people using 400's in the BRA thread over on Accurate Shooter. Obviously more options are better, but if that's all you have then I'm sure you can find something that works. Like others have said just don't jump into a really hot load from someone using 450's or BR4's.
If you're worried about accuracy of the 25 CM, don't be. I'm an okay not great shooter, but borrowed a local pro's gun during a match at 1000 yds, went wayyy too well, just effortless to hit steel IPSC plates. The short action and quality brass make that the easy choice if you're set on the...