With the 1-8 twist I am wondering “on average” with factory or hand loads what is reasonable to expect regards a 3 or 5 shot group in the 100-200 yard range with supersonic bullets. I am in the market for a new upper for a hunting rifle was looking hard at the 6.8 SPC but then noticed that a 110 grain 30 cal TSX could be had at 2400 FPS vs. the 110 grain .277 TSX at 2550 FPS or so with non overpressure loads. So roughly the same for velocity, but I don’t know about accuracy.
It is like anything else - it depends on the exact gun, shooter, and ammunition.
I shot this with my 9 inch and AAC suppressor and factory ammunition and Aimpoint Micro. I then put on an Eotech and did about the same. This is 100 yards.
Here’s a 200 yard target with reload using 125 TNT’s chronied at 2120 fps!
Shot with 16" Carbine. The 6.8 might get you a few more yards in range, but you got to get a special bolt/mags. The 300 Blk is just a barrel change.
Of course as rsilvers pointed out it will depend on the individual barrel, shooter, bullet and load. On “average” with any of my 3 (5.56) rifles I can with good bullets like a 65 grain Sierra gameking, a good load (usually TAC or Varget) get at least 1.5 MOA, and in many cases better. The 62 grain federal fusion cartridge shoots in all 3 at 1.5 MOA or better for 5 shots. As an example of what I am talking about if you took 10 AAC 16 inch uppers and shot them with 110 grain Barnes Vortex loaded cartridges would at least 7 of the uppers shoot into MOA or so?
Hey guys what about accuracy on subsonic loads?
I have a Noveske 10.2" and have only shot my subsonic handloads through it. I have loaded seveal different “heavy” bullets 220-240 gr using A1680 and have not been happy with the accuracy. The best I have been able to acheive is a 3+MOA. I am sure it has something to do with my reloads but I have not figured it out yet. Recently, I ordered several different factory loads to test fire for accuracy but am still waiting for them to arrive.
I’m getting <=1" at 100yds with Remington Match out of my 8" 1:8 Noveske barrel with a 762-SDN-6 on the end.
Demonstrated towards the end of this video…
Rem Subs at 25 yards! And yes they shoot perfectly out of my unsurpressed 16" carbine! Get very close to the same with my cast 170gr GC load of 12 grs of IMR4227 -this not a true sub but close enough fo me!
I get ~1.5 MOA with a 16" no-name upper and 115-gr. Remington factory ammo. I use a 4x Leupold scope with duplex crosshairs for optics.
Okie John
I put together a 300 BLK upper using an AR Stoner light weight barrel from Midway. It shoots under 1 MOA all day long. Best group so far was .333 inches for 4 shots with the 5th opening the group up to .9 using my reloads and a Leupold MK 1.5x5 MR/T scope.
I would say that mine averages around 1.5-2 MOA for 5 shot groups. Some loads are better, some are worse, and this is including loads with cheap bullets (ie 147 gr pulls). The 110 v-max tends to shoot better. For handloaders it seems the 300 BLK is a little more finicky regarding neck tension. I have started using a Lee FCD which seems to be improving accuracy, so this is far from the end word on accuracy.
I have found the 115 gr UMC ammo to be quite accurate, averaging around 1.5 MOA.
Of note - all of the above were shot with an aimpoint, which is obviously not the ideal bench optic.
I don’t think the 300 BLK is any different in terms of accuracy potential than other AR platform rounds.
Oh, forgot to include, it is a Wilson Combat 16" medium weight barrel.
I would like to do the Sniper’s Hide 30 round challenge with my 9 inch 300 BLK and factory ammunition, but it is forecast to be in the 30s for temp here and I am just not up for freezing.
Come down to Fl 
Thanks. That would be good, or I could go to Barnes’ 300 yard indoor range. Actually I should just buy one of those propane heaters.
We get MOA accuracy all day without even trying with our Noveske 300 BLK set ups. We have a 14.5 and a 18" custom 300 BLK for making major power factor (back when it mattered), as of now both guns like the Remington Premier 125 OTMs the best.
I just put together an upper using a Wilson Combat 16" barrel and it shot 1.5" groups at 100 yds open sights off the bench. I was pretty surprised for open sights. Load was 15 gr h110 with 168 gr matchking at 2.260 oal. I didn’t take my chrono with me, so no velocities known yet.
(and this is my virgin post)
motoduck
At what distance are you getting 3-5MOA? If your not getting .5" or less at 50 yards with subs something is wrong with the shooter or firearm.