I recently sold my 308 because I wanted something lighter to carry around deer hunting. My 308 was very heavy, with an aftermarket stock and a heavy profile barrel. It shot well, but wasn't really practical for anything other than shooting prone. I started looking at 6.5 Grendel because it will fit in an AR15 platform, which allows for a light and handy gun. I wanted something that I could carry all day but still shoot out to longer ranges for fun. Some guys are reporting they are getting hits out to 1000 yards with the Grendel, but I think 7-800 is more realistic. The 6.5mm bullet has a very good ballistic coefficient which can translate to good downrange performance, but the case capacity is too small to drive the bullet at high velocities like the 6.5 Creedmoore, .260 Remington, or other 6.5mm long range cartridges. Still, it has a much better range than .223 and delivers a lot more energy on target. It's more than adequate for deer sized game.
I ended up building an upper around an 18" lightweight barrel from Underground Tactical. It came with a matched bolt, which is nice because there are actually 2 different bolt specifications depending on how the barrel was chambered. Grendel purists will tell you that only the original chamber from Alexander Arms is a Grendel, but there are several different variants out there. Mine is a "Grendel II" chamber, which has a different throat. The barrel is very nicely finished, and since it's a lightweight profile it flares out slightly at the end so it can still be threaded 5/8-24 for .308 muzzle devices. Many Grendel barrels are threaded with a smaller thread size, which then requires a thread adaptor.
I tried to keep it fairly light without spending an arm and a leg, and I went with just a plain jane free float forend. The one really heavy part is the scope, which I took off my .308. With the scope and an A2 lower receiver the whole rifle comes to 9.5 lbs. A good portion of that is the scope, which I mounted on a 20 MOA canted rail to give me a little extra elevation to play with.
So far I'm pretty happy with it. I only have about 60 rounds through it, but it's showing some decent accuracy potential. I wasn't expecting it to be a bughole shooter with the lightweight barrel, but I figured if it shot around 1 MOA it would be good enough for what I'm trying to do. I've only tried one bullet at this point (123gr Nosler Custom Competition), and it seems to like a max load of H322. That's giving me just under .8 MOA. Group size kept shrinking as the powder charge went up, but the max load was showing some ejector marks on the brass so I'll probably back it down a couple tenths and see how that shoots. My chronograph didn't catch any of the max load shots, but a half grain below that was averaging 2,313 FPS so I would guess it's in the neighborhood of 2,350. According to Hodgdon that load should generate 2,434 out of a 24" barrel.
A lot of guys recommend IMR8208, but when I tried it I got some serious pressure signs and accuracy was not impressive. I still need to try some other bullets. The Hornady Amax 123gr is supposed to shoot very well but I haven't found any in stock, and the Lapua Scenar 123gr is supposed to be fantastic but it costs $10-15 more per 100 than anything else. I also want to try some CFE powder from Hodgdon, since that reportedly gives very good velocities without excess pressure. I'm going to keep experimenting with different loads and hopefully improve the accuracy, but I'm pleased with what I have.
