ak2m4

Sadly the whole hop chamber situation is a complicated. Prowin / Rotary designs don't work in every brand, add in after-market inner barrels and buckings and get's more complicated. Best you can do is research your own make and model, buy and try. I'll always recommend never to change the hop chamber unless there is something wrong with it. I would never 100% recommend a hop chamber unless I had fitted the same one to exactly the same AEG, that includes the inner barrel, bucking, nub etc. Even then manufacturers can change the specs from batch to batch. Minefield....

Thanks @L3wisD, got some Maxx units here so when I get some more time going to try them and may give the rotary's another shot. Can waste an entire day on stuff like this 🙂

@L3wisD how are you finding the Prowin with the B12? I spent a whole day trying to get a rotary to work with an E&C gearbox and gave up.

Hop units can be a hit or miss upgrade sadly. You must be prepared to accept the fact that any change in a hop unit could result in other problems occurring.

Yeah book was amazing, they should have made it into a 10 part series instead of a movie

@Iceni yeah stock springs are M120's, maybe try a M110 perhaps if you have one lying around, if not let me know and I'll sort you out one.

that is perfecto 🙂

Just £5, have sent you a PM with details

Definitely a M110 or a M120 buddy. If you want I can send you a ZCI M100 out today which are dead on from my tests. Should get to you tomorrow 🙂

I've noticed this with SHS springs now and then. M110 tend to go M100 packaging and in some M110 you find M120's. M110 and M120 look very similar, Post a pic of the spring and I'll see if I can eye-ball it for you. I've spent so long looking and testing these springs lol

As you're new to upgrade work I highly recommend getting another AEG first and then looking to upgrade one or the other. This means that when / if you do break it you'll still have something to use. That said a set of SLD / Rocket 13:1 gears with a High Torque motor is a good place to start once you've made sure the compression parts are working as they should. If not then look at getting a new cylinder head, nozzle and piston head. I'm just firing from the hip here but hopefully it gives you a little understanding of what to look for.

What spring brand was it? Sounds to me like you may have a M120 there but each brand is different in how they rate springs. What FPS were you getting before you changed to the included M90? Worth checking the hop chamber and bucking for any misalignment / damage.

I keep saying the same thing lol.... maybe today's the day 🙂

Thanks Lewis, popped you in a free ZCI 60 hop 🙂

Ahhh still love my G&G GR300S, my first rifle. Back in the day (2003) the stock gearbox didn't make it past the first day lol Early May I'm getting in a supply of CNC machined bevel's / complete gearsets together with CNC machined pinions from SLD, they really are the nicest set of gears I've seen for the price. Basically SLD (or whoever is operating the factory) took the SHS design and improved upon the quality massively, from what I've seen they are appearing in new CYMA gearboxes.