Bullgear CNC Machined Hop-Up for A&K / Cybergun / Classic Army M249 Airsoft AEG

"This is the only Hop-Up you should every be running in an A&K or Classic Army M249. If you have one of the M249's this is made for, buy this up while it's still in stock. This hop-up unit completely eliminates all the issues with the stock units. It feeds flawlessly and when installed correctly with quality parts (bucking, Barrel, ect.) allows for extremely consistence shots.

"Works a treat and nicely fixes the weird feeding the stock hop is prone to on an A&K M249.

I got a Gen3, which uses four screws to hold everything in place.

Bullgear recommends a purple Prometheus bucking - do what they tell you. I tried doing some thinking (Mistake #1) and using a Red, since my gun is running ~390fps. Big mistake - doesn't work.

Put in a purple? Needs less than half the adjustment range to hop 0.28's.

Great hop unit - just make sure to listen to Bullgear and use the right bucking!

"i have the gen 2 version of this (has two screws to pull the barrel clip up, and a screw for the hop up arm not a lever) and i have been very pleased. Truly a drop in mod to correct the hop up issue from A&K. I did have to run a slightly longer nozzle to achieve full compression but not a huge issue, for me 21.6mm was the correct nozzle length and i put a slight chamfer on the end of mine. checking against my chrono (acetech5000) im getting deviations of about /- 2fps @23 rps which is great for me. This is in a MK2 with a 510mm barrel.

"I was worried about the fitment on my Stoner MG but it fit just like the original. The square window lets me finally flat hop this beast. 100% would recommend.

"This is what we've been waiting for. Feed issues solved, accuracy increased, and it looks great. This is a must have for HPA conversions.

"Awesome hop up and a much needed improvement over the stock hopup. You can use normal hopup pieces like the Prometheus purple bucking. It's nice that this hopup chamber has a square opening so you can flat hop or r hop your barrel now without modification to the round nub hole window with the old a&k setup.
The new metal c clip is a improvement over the crappy plastic one enabling you to make fine adjustments to even out the barrel. It's a tight fit but will go into the barrel groves when you gently tap it in.
Well worth the price for the extra options in buckings unlike the old proprietary bucking

"Awesome hop up and a much needed improvement over the stock hopup. You can use normal hopup pieces like the Prometheus purple bucking. It's nice that this hopup chamber has a square opening so you can flat hop or r hop your barrel now without modification to the round nub hole window with the old a&k setup.
The new metal c clip is a improvement over the crappy plastic one enabling you to make fine adjustments to even out the barrel. It's a tight fit but will go into the barrel groves when you gently tap it in.
Well worth the price for the extra options in buckings unlike the old proprietary bucking

"Displeased with the design of two small screws. It’s good in theory, but my barrel has a bit of a tight fit with the clip. I was screwing both sides in evenly and one screw head snapped. The other managed to keep going. I even applied force when it started to get tight since I figured I already have to drill one out so “why not.” Weirdly, it did just fine.
However, another flaw is that the bottom of the barrel clip still doesn’t seem to sit completely flush with the hop unit, meaning it doesn’t slide into my CA outer barrel. I suppose I’ll need to work on it some more, this time grinding that down.
The other one I installed in an A&K was a lot smoother, which is why I know it works well and can’t rate it poorly