Review of the Adams Arms Piston Upper on a Precision Guncraft Lower

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Here is a review of the Adams Arms piston upper on a Precision Guncraft Lower by Jeremy S. on YouTube. Jeremy goes over his build, the Adams arms piston system, and shooting the rifle with out having adjusted the sights.


“Alright, last few shots of the day I am going to put a few rounds through my AR 15 that I built recently. This uses a Precision Guncraft lower. They are down in Boise, Idaho I believe. It is very nice it is a billet one piece. I have an Adams Arms piston upper on it. We have an adjustable gas block, it has off which is great for suppressor it means that the action will not cycle, and it has low, and high. The other side of the lower, I like it a lot I wanted a billet, but I know they are hard to find (anything AR) Precision Guncraft does have lower in stock though the last time I looked.
As you can see I have an ACE skeleton stock on it. I like it because it is simple and light. One thing to keep in mind is these come in different lengths, the one you see in this video is actually a rifle length buffer tube so you don’t want to put a carbine length buffer inside of it. This is a common mistake, it will break your upper or at least your charging handle. Also on the front of my rifle I have a Rainier Arms mini comp. Troy flip up sight on the front, Magpul on the back. They were both Magpul but this is the gas block and it gets hot so I had to go with a metal sight.


Anyway, nice simple build. I have a suppressor on the way which is why I decided on an adjustable gas block and I decided on a piston build because with the extra pressure from the suppressor I guess you get a lot of gas coming back at you through the action when it opens. With a piston all that extra gas goes out the front here. I can put it on low because the pressure increases with that suppressor the time that the bolt is in the barrel increases so putting it on low will make it cycle in a more normal fashion. High is what you use for everyday use and you can even turn it off which would be the maximum suppression because the action doesn’t cycle and none of it will come back.


So anyway, let’s put a few rounds through this guy. While I am waiting for this car to drive by, mostly I have Magpul PMags but I have a couple of these Troy Battle Mags that I picked up recently and will give that a shot but I expect them to work perfectly fine of course.


Alright I am going to shoot at that pepper popper out there. I haven’t sighted this rifle at all and I haven’t adjusted these sights. This is as they came from Troy and Magpul, so they aren’t even matching sights. Let’s see if I can hit anything.


If I take my time I will not miss. Cool! Let’s put a couple shots on that tank up there just because. And empty Mag.


So what I have just done is put the gas block to off. Presumably the action should not cycle when I fire now. So let’s see if that’s the case. Pull the trigger again and nothing. That works, very cool. It didn’t eject and cycle the action.


Let’s put it on low and it should fire on low just the same. Nope didn’t feed. Ok, I am going to put it on high which is what you are supposed to put it on for normal shooting. These are 55 grain reloads from Freedom Ammunitions. Yep, 5 in a row on that pepper popper. Pretty cool, I am loving it, feels good.


I have a few rounds left and I am going to shoot at those chickens out there. These are maybe just 20 yards so I don’t know how the sights are going to line up with that, but I’m going to aim for the top right chicken there. Dinner tonight!



While I am here lets try this Thermold 20 round magazine. These are really cheap. A lot of people seem not to like them at all, but I don’t know let’s see if it runs for me. Seems to work. It’s empty just didn’t lock back. It works.”


For more reviews on Adams Arms’ piston uppers, parts, and rifles Click Here.
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