GIBBZ ARMS G4 SIDE CHARGING UPPER RECEIVER

This is the perfect AR upper I even built one off the 308 platform that everyone wants when I go to the range. The + & - of the system is the proprietary cam pin and if you are building a piston upper Gibbs site offers a brass piston fitting for the upper and you can also order an extra cam pin, I highly recommend doing both of these things. I have built about 50 ARs with this upper and I have yet to get one back or have anyone not satisfied. This action is exceptionally smooth I have never needed the forward assist. You get that billet smooth look, with the potential for a very light gun and I have never had extraction problems because the ejection port is so big. The only 2 draw backs are the charging handle is a bit short so at times you hit your knuckles on the scope mount (Gibbs now makes a comp handle on there site) and you need a Geissele rod to install the barrel but this is just another excuse to get another tool, there is also a Brownells version of that tool on this site. To sum it up for the money you can't best this upper, I don't have to waist money on a way to expensive Charing handle and on mag changes my cheek weld stays intact this gives me faster fallow up shots. Highly recommended and with Brownells lifetime guarantee it's a no brainer.

Put this upper on a SBR with a 10.5" barrel. Looks great. I never used a forward assist in the Marines, and the dust cover is a waste of materiel. Over a thousand break in rounds and no malfunctions. My only problem was putting the barrel nut on. I turned a barrel clamp on a lathe and went that route. Overall I think it's a great unit, runs good, looks good. If you want to step out of the normal AR scene pick one up.

The design of the Gibbz side charger is nice but the threading for the barrel nut and the tactical rail was way out of spec on the unit I received.

I've build twenty one AR-15s with left side charge. Fifteen utilizing the Gibbz left charge receiver with my choice of bolt carrier. Six with the excellent ASA left charge that includes their proprietary bolt carrier. Both fine products.

~ Bob, Houston Collection

I purchased this to use for building a rifle for 3 gun.

I installed a Samson handguard to it, it required fitting of the handguard tabs between the upper and the handguard. These are anti rotation tabs.

I put a Criterion barrel on it and that fit very well.

The upper to lower fit was tight. I used a tactical machining lower that I got off a prize table.

When you charge the upper, a slide comes back with the charging handle. This hit my lower receiver where you screw in the buffer buttstock tube. I had to either file down the lower or the charging slide. I relieved a little bit on the charging slide. I don't think it affected the functioning at all.

I added a JP LMOS bolt carrier which works great.

I practiced a little with it and then shot the rocky mountain 3 gun match...about 200 rifle rounds, then the noveske 3 gun match....about 125 rounds. It is holding up great and I had no malfunctions with it.

The brass does make a mark on the rear of the ejection port cutout, since there is no brass deflector on this thing.

I also noticed it kicks the shells to about my 5 oclock. But this could also be attributed to my gas system.

I would buy another one.

I used a magpul BADD lever and this allows me to rack the bolt and lock it to the rear with one hand.

THIS UPPER IS IDEAL FOR ANY OPTICS THAT EXTEND OVER THE CHARGE HANDLE AREA. MAKES CHARGING AND CLEARING THE WEAPON A ONE HANDED JOB. IT ALIGNS SMOOTHLY WITH THE YHM SLANT HAND GUARD MOUNTED. THE TOLERANCES ARE VERY TIGHT, WHICH IS A PLUS,BUT BE PREPARED TO HAVE TO TAP THE BARREL TO GET IT TO SEAT.

My previous comment was a novice mistake. The bolt catch will engage. I have requested my old review be removed.



I have had this upper for about a month now and have been struggling with the Adams gas block. I originally intended to use a standard hand guard but In order for the rifle to cycle properly the piston must be spaced 0.015"-0.025" from the gas block when the bolt is closed. With the bracket provided by the Adams gas block system in place this specification cannot be met (the gap is over 0.025") and the action short strokes . I was forced to use a free float hand guard and now it works flawlessly. Since I tried 2 different barrels from different manufacturers with same result I feel the problem is with the Gibbz upper being a bit to long.

Ok this is great for a scoped rifle while laying prone.



If your rail buts up even to your upper then this will work if. If it has any prongs it wont work.



I used a JP tube hanguard, Larue scope mount and Magpul UBR stock. Love it.



One complaint would be its a little heavy. I would think they could lighten it.



Also one neat feature is the spring loaded trap door for removing the bcg. Also the gas tube port appears to be threaded in maybe for a piston bushing?

As Uppers go not cheap. However very well made and very well engineered means flawless function, even with a Caldwell Brass Catcher mounted to it.



The only potential negatives are no forward assist or dust cover. However if you keep your rifle clean you really won't ever need a forward assist and I've always felt the dust cover was basically "eye candy".



BTW, combine it with a Gibbz handguard and you will have to look long and hard to find a system that allows the barrel to be mounted and torqued with more ease. Screw on the handguard adapter, line up the notch for the gas tube with a drill bit or gage, clamp the Handguard Adapter in a padded vice, and then torque the barrel nut using the Gibbz tool, a crowfoot and torque wrench. At no point do you have to actually clamp the Upper, all the force is applied to the barrel nut and Handguard Adapter. Unfortunately, Brownell's doesn't carry the Gibbz Arms Handguards at this point so you have to order direct but that is Brownell's loss.

I was looking for a non proprietary side charging system for my AR that didn't require me to modify my bolt carrier. I also didn't want to have the handle flying back and forth as the bolt cycled. This setup gave me exactly what I was looking for. This is one of my favorite AR uppers. I actually own two.... If you are going to use a scope on your AR and want a setup that works flawlessly, this is it. If you are looking for an upper with a dust cover or forward assist...keep looking.