TM M870 reservoirs leaking

[Proffrink]

I recently bought two second hand M870 gas reservoirs and they're leaking from the base plate (fill valve and output valve are fine).

I've done the following:
- Left the o-ring soaking in silicone overnight before replacing
- Replaced pins with allen bolts and nuts before tightening them down to combat the warping around the edge of the reservoir
- PTFE/Teflon tape
- Removed o-ring entirely and attempted my own seal out of RTV
- Reformed the tank slightly with some gently persuasion from a hammer as I noticed the fit of the base plate was loose even after sitting with the bolts screwed down for a few days

None of these have worked and I'm fresh out of ideas. Does anyone have anything else they've tried? These are the most troublesome gas containers I've ever owned. Any help is appreciated - thanks.

I should mention I did see this thread: http://forums.zeroin.co.uk/showthrea...-M870-gas-leak - it's not helped me unfortunately. The leak is certainly not from the stock where it connects to the body as I've replaced the o-ring there, and although the cylinder is leaking too I'm working on that and the reservoir is leaking immediately after filling not just when I place it in the stock.

[McKillmore]

Re: TM M870 reservoirs leaking

Did you ever get this sorted? The only advice I can give is the old hot water trick. I've used it many times on GBB pistol mags with great success.

How I do it is I put an empty (of gas) mag in some boiling water from a kettle for at least 60 seconds.
Then using a pair of gloves to handle the mag (it'll be pretty hot), I gas it up fully and leave for another 60 seconds.
Vent the mag and repeat process until the leaking stops.

Like I said though, I've used this on pistol mags so I don't know if it'll work on your shotgun gas tank.

Good luck

[Proffrink]

Re: TM M870 reservoirs leaking

Sorry that I never replied to this. I eventually gave up, sold my magazines as leaky and bought a couple of CNC'd ones plus tapped a non-leaky one for HPA.

Thanks for trying to help though. Maybe I could have got it to work eventually - I've had to fix up countless second-hander pistol mags but these ones just defeated me completely.

[McKillmore]

Re: TM M870 reservoirs leaking

Update in case anyone else has this problem. One of my mags was leaking after today's gameplay. I dropped the reservoir in a bowl of recently boiled water and left it there for half an hour. Works absolutely fine now.