ZCI CNC Aluminum One Piece Rotary Hop Up Chamber Set for M4 / M16 AEG Rifles

"I have 2 of these. 1 in my sr25 and another in my de aeroknox m4.i haven't had any issues. Also why am I going to replace all my parts just so I can use a Maxx chamber then there's nothing inherently wrong with the gun. I would prefer the g&g chambers but those are hard to come by. If you have a gen 2 combat machine or G2 5.56 (don't get the 308. It doesn't have any advantages over any other sr25 or hk417) do not change you hopup chamber. The whole reason I bought this is polymer ZCI Chambers aren't readily available. I can't say anything about the quality of the bucking. It looks like a winter bucking but I don't use those. The silicon is sticky and can cause jams at least with maple leaf. Not saying you can't use a regular maple leaf bucking. They do what they are supposed to do and don't feel like they break easy

"Bought this since I could get my double eagle hopup chamber apart and haven't had any issues. It euns just fine ad feeds just fine. I'm actually putting one In my cyma sr25 (,only because the stock barrel assembly is really glued I tried scraping the threadlock off and then even with a flat head the c clip willing cone off. Not that I was going to use the stock inner barrel anyways). But if you need a cheap hopup changer and you can't get a g&g/don't have an extra laying around this is the way to go

"Feeds well, easy to set up, comes with an ok bucking and nub.

Worth every penny imo

"Its really good, feeds perfectly and hops really consistently in my custom m4. The only "issue" is that the hop up is red rather than the blue shown, but it doesn't really matter for me.

"bit loose around the barrel/bucking, but you should be Teflon taping that joint anyway. couple extra wraps made it nice and tight, now it works perfect. easy to adjust and stays adjusted exactly where you put it. well machined and looks/feels good. no real complicated other than it being a bit loose, but that may be intentional to allow greater parts compatibility. have Teflon tape on hand and you're good.