ghostwalker

i would guess you do the usual with your clone mags @impulse . That being putting the silicone sealent around the base of the main magazine body to stop the leaks from the base. occasionally regrease the o-rings on the fill valves.

I usually use ulra-air as a gas for my mk23 so wonder if thats the issue

I haven't done the silicone sealant around the base. I try to take them apart as little as possible because it's a faff getting the baseplate back on. I use the regular nuprol 2.0 gas in mine, so a bit more lubricant in than the ultra-air, though I do like ultra-air as well. I just never leave ultra-air in my mags as I've heard it's dryer. One of my mags was leaking when I bought it, but the o-ring was crap so I replaced it with an o-ring from one of my (many) leaky TM mags and it worked like a charm. Haven't had any issues since.

cheers @Impulse I may have to try and order new fill valves and try a different gas in them just incase then.