EMG x Retro Arms CNC Machined Aluminum Rotary Hop-Up Unit for M4/M16 Series Airsoft AEGs (Color: Blue)

"Good so far, haven't used this in a game yet but when I do I'll update my review if I can.

First impressions, looks good pretty easy to put together, and easy to install. Comes with a RHOP/Flathop arm and a standard arm.

Also comes with 3 O rings, 2 of them attach to the back of the unit where the adjustment nob is and 1 attached to the feed where you insert the magazine. I recommend not putting on the 3rd o ring because it's optional and also causes your mag to unwind and not feed if you're running hi caps (dk about mid caps).

The nub is tight as frick and can not be turned with just your fingers from the dust cover, you'll need to take apart your gun and take it out and twist it with your hand.

Mine also had a bit of wobble (like a millimeter of wobble) but it shouldn't be a problem because the magazine serves as a point of stabilization and you can tabe the wings of the unit if you want.

Feels quality overall and for now I'll rate it 5/5

"Works really well and is really nice with my maple leaf 🍁 bucking

"I bought this to upgrade the hopup unit for my EMG Noveske Gen 4 Aeg. I paired this hopup unit with the Prometheus Blue bucking and nub. It has worked flawlessly so far, but I did have to modify the hopup a little bit. Since it does not come with a tension spring I had to figure out a way to keep it flush with the nozzle. I did so by wrapping a rubber band around the front end of the hopup. Now the nozzle and hopup are flush and the consistency of shots has definitely increased. Not to mention that the upgrades increased my fps from 353 to 361. (With .20s).

"Make sure to not over tighten the circular silver screw near the bucking on the front of the unit. If you do your gun will misfeed or jam because the inner barrel will be too tight.

"great hopup unit. few modifications were needed to my maple leaf rubber, the lips were a bit too far out to the point where the bbs dont feed up. i had one flaw with this, if you use the inner barrel secure nut with a 5KU outer barrel, the hop unit will not be able to be pushed forward enough. luckily you are able to use a regular brass ring that comes in a stock hop unit and it will be pushed forward enough. this hop unit comes with everything needed to install it except it has no spring included to be pressed against the outer barrel. you will need to use one from your stock hop. you also have an option to have an o ring at the bottom of the feed tube to stop bbs from falling out. the o ring is included

"I put this with the Angels Custom 6.03 barrel and it is shooting great the hop up is very sturdy and sensitive at the same time (which I love). I recommend this for anyone trying to upgrade their gun. 10/10

"Great unit! The adjustment wheel out of the box is very tight and hard to turn so I recommend silicone oil on the o-ring to make it easier to turn. Come with 2 arms(flat/concave nub and standard arm) that but fit nicely in the unit. For the price can’t go wrong with it! I give it a 7/10

"Overall, it is a nice hop up, and it works great with a Prometheus barrel and Prometheus purple bucking. However, it is machined poorly and had metal bits around the cuts for the o-ring cut-off. They were easy to remove with some needle nose pliers though. I decided to try this because of the cheap price, but I am still going to stick with my favorite Maxx ME Pro hop up units.

"Keep in mind these are designed for the Retro Arms outer barrel lug. Though it can work for other TM spec M4 outer barrels it works best inside a Retro Arms outer barrel attached to a Retro Arms upper as the specs are slightly different than most TM spec M4s. I dont really understand why EMG did the endorsement since almost no one runs full retro arms M4s because the body parts are Very expensive and sort of proprietary. Retro arms has High quality parts for sure but look out for their beautiful outer barrels and hop chambers not working well without each other.