Of course our barrel. We choose the stiffest upper we can find. I would run our AR10 against most bolt guns.
Overall “yes”:Is that the barrel that has the hollow outer core with tubes running down parrellel of the inner barrel? Looking at it from the muzzle end it looks like a honey comb???
It’s a solid barrel that is cored. It has another primary advantage on an AR- it runs cooler. In this case actually “ cooler” as it is a radiator not an insulator. Rex does a great video talking about the barrel and the results of shooting the AR with multiple factory rounds is discussed.
Here is my mod to keep the BCG centered. The uppers I use are the heat-to-fit BCM to competition barrel extensions from Whiteoak Armaments. The BE is 0.300 longer, and 20 TPI instead of the Gi 16 TPI. The BE is like a miniature AR308 BE.I don't have any understanding for why upper to lower fit needs to be tight. There's likely a good reason that I'm missing (other than user confidence in the firearm), but to my way of thinking the important part is the upper's fit to the barrel and the BCG as all of the important interactions happen there.
None the less, a couple of my builds have featured that little polymer wedge. There a few vendors who offer a drilled & tapped grip screw with a set screw in the center of it. Running the set-screw out when assembled takes any vertical slop out of the upper to lower fit. I *think* that I have one somewhere, but I've not tried it.
I've used a Seekins IRMT-3 monolithic upper/handguard on a couple builds with good results. I used them specifically to get the flat bottom on the handguard. Other builds I've used Aero or a generic thick walled uppers with Apex Gator Grip handguards.
We regularly demo 500yd - 600yd hits when using our AR15--- given the ammo the gun likes-- stock POF. Our main focus is the optics being able to go CQB to 500 yds instantly with any "red dot" or any optic. In this case the optic is the unit in front of the scope -- Alpha TARAC. We build those custom to any gun allowing an instant switch to a second point blank range.
It gets interesting when we get to a larger weapon like a 6.5Creed or the .260Rem pictured. We demo a 100yd round than an instant 1000yd round on a man size target. To clarify- we don't demo- the operators are the shooters. A fun note: we were demoing with a sniper team and ran the 100yd impact and jumped to the 1000-- guys in the pit at the 1000-- he shoots three rounds... the pit guy comes back over the radio "you just dropped a 3" group". Made the shooters day, year, still talks about it.
Lucky --- a bit.
Do we consistently engage man size guys at 1000'yds-- every time we go out for demos. We have engaged 1500yd targets regularly- as long as we can see splash. Will the guns shoot sub 3/8moa-- "yes". With factory ammo and more than likely more than one type. Several top manufacturers will produce AR's with these capabilities.
We do press in every extension into the upper. Switch over to a Savage style nut system. Run a "very" adjustable gas block. Of course our barrel. We choose the stiffest upper we can find. I would run our AR10 against most bolt guns.
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