18" stainless hunting barrel will shoot 6.5 grendel and 264LBC ammo, they have been tested with the Hornady 123 amax, Black Hills loaded Les Baer ammo 123 Amax and 123 SMK, AA 120 Nosler, Wolf 120 sp and several handloads producing more velocity than the AA loaded ammo. 1 in 8" twist. The chamber has a .297 neck 1.5 degree throat angle for better accuracy and to prevent splitting the case necks.  Barrel is a SPR contour, mid gas,  6R rifling.
Muzzles are threaded 5/8-24 for a better selection of flash hiders and brakes.
These barrels will use standard 7.62x39 bolts or our 9310 alloy 7.62x39 superbolt.

IMO bullets in the 100gr range work better for hunting with a case of this size. The 100 Nosler, and 100 gr Barnes TTSX will reach apx 2775 from a 18" barrel using 27.5-28.2 gr of 10 x. Work this load up slowly. The 100gr Lapua is a very good target bullet in the same range ( 27.8gr of RE10x with the 100 Lapua loaded to 2.295 is under 1/2moa)  The 123 Amax and SMK are also very accurate and can be pushed to near 2600fps.  If the 120 TTSX expands down to 1800fps it could increase the hunting reliable terminal range to 400 yds.

quote from Arne B.-
Back when brass cost 38 cents per piece, getting only 4 loadings on a case before seeing split necks was bad. Now, lapua brass costs $1 per piece, and getting the most life out of brass that you can is very important.

In the 295 neck chamber, 10 reloading cycles with no split necks was the norm. As a matter of fact, I NEVER threw out a case with the .295 chamber, but did throw out brass with the 300 neck chamber.

These are not "Grendel" barrels, they are not chambered to work with "Grendel" bolts. They will however shoot Grendel ammo.

If your priority is shooting targets out to 300yds mainly with some hunting then the 6.5 makes sense, there are some very good 264 match bullets and have had very good luck with 100gr lapuas. There are only 6 factory Grendel loads so reloading is likely to use some bullets. If your priority is more hunting with some target shooting the the 6.8 may be a better choice  for hunting. The BS spewed from the Grendel forum about these chambers not working with Grendel ammo or Wolf ammo or steel cases is just more BS to steer thosethat don't know back to AA just like the special bolts that AA uses and special muzzle threads on the AA barrels and the trademark that was finally released. Steel cases are thinner than brass cases, just measure one to see for yourself.