(HELP) A&k m249 inner barrel moving.

[Brotherhood98]

Hi all, I have recently got myself a brand new a&k m249 (mk2). I took the outer barrel off and the inner barrel+hope unit came out with it. Now I have put the gun back together, it is sliding forwards and backwards. Have I broke something?

View attachment 44683

View attachment 44684

 

[Seejay]

Did you put the spring back on the front of the hop unit before reassembly? Shown in this video at 0:53 

 

[Brotherhood98]

I had a quick look round and it turns out that spring had dropped off at some point without me realising. I evenutually managed to get the barrel off again (not very easy without that spring in place!) But it came out with that much force I've ripped the hop up bucking. 

From watching a video online if pretty confident I can put it all back together but the other thing is there's a small brass band that needs to be somewhere in the assembly and no videos I've seen showed where that part needs to go 

 

[Seejay]

The brass band is to stabilise the inner barrel in the hop unit. Once your inner barrel is installed back into the hop unit, put the white barrel clip back in place and slide the brass band over the end of the inner barrel into the front of the hop unit. With the video paused at 0:53, it sits in the very front of the hop unit between the spring and the white barrel clip. Grab yourself a new bucking too, the damaged one may cause you some issues. 

 

[Brotherhood98]

Ah ok, I thought that's where it might have gone, but didn't want to start putting it in places it shouldn't be. I've already ordered a madbull blue shark 60 degree bucking as a replacement as it is recommended for 320-370fps builds, the original one was ripped into 2 pieces, the o ring around the dial for the hop up looks pretty dry/cracked so could probably do with replacing whilst I'm at it. Do I need anything specific or can any o-rings be used?

 

[Seejay]

Just take the O-ring out and take it to your local hardware store. You just need a like for like replacement. If you have one sitting around that is the same size then try that one. 

 

[Brotherhood98]

Excellent. Thanks for the help mate ?