Balancing Lightweight & Performance: 6.5 Grendel Update: 1000yds
This is why I got out of .308/7.62 NATO. I've owned a bunch of AR10's, and most of the guys I know have AR10's as well. I wanted an AR10 since I was a kid, so in addition to all the AR15's, I had to have several. As I started to compete with the AR10 in .308, I soon realized that I was handicapped by the caliber against 6.5mm's, 7mm's, and other high BC-spitting cartridges.
That led me to get two .260 Remington AR10's, the first a DPMS LR-260, the second a custom-built gun from GA Precision, which I still have. Weight of the AR10 has always been an issue, and the matches I like involve 2-man teams, lots of movement, land nav, while carrying all your equipment. My LR-308 and LR-260 were heavier than a SAKO TRG in .338 LM, so that drove the way I spec'd out custom builds from then on.
In addition to the .260 Rem., I knew I wanted a lightweight AR15 that had more reach than 5.56, with more energy. I got a 16" 6.5 Grendel barrel/bolt combo back in 2009, and the cartridge slowly grew on me, eventually displacing .308 from my personal use.
My recent build uses a Lilja barrel, and it's a shooter. I went with a really lightweight profile, what they call the Wasp, which has .650" dia. under the handguard, .750 gas block journal, and .740" fore end with 5/8x24 threads. The work Lilja does is top-notch, and it shows on these barrels.
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One of the main things I like about the cartridge is that every piece of factory ammo was meant to run in an AR15 gas system, unlike .308 Winchester or .260 Remington. This one is shooting really well with the factory Hornady 123gr SST.
With the way I have it set-up, the gun is very light and maneuverable, yet I took it out to 1045yds on its first trip, hitting a 22" steel gong. At 470yds, the rounds were impacting steel on top of each other. Even with the bipod, it still is under 9lbs at 8lbs 12oz. I would have zero problems carrying it in the mountains on a hunt.