I've been finding that most of the HPA conversions when filled to 3K will leak down to 
around 2.5K over 2 to 3 days, then stop at 2.5K.
I've started filling only to 2.5K and everything is fine. I know that the regulators will run at just over 1400psi
when the tank is maxed out and will drop to just under 1400psi when the tank drops below 2K... this 
is pretty normal. But it looks like the valve's seal limit is reaching its Max at around 1450psi.   
Is / has anyone else had this happen?
Of my three, two will do this and one not at all. Of the two that do leak down, one will only do it "some times:" I guess it depends on how the valve ends up on the o-ring / seat after that last shot?
kind of annoying   ..... although 2.5K still gives a pretty good shot count I guess.
Roald.

The 850 Store

I bought my own 48ci bottle and one of Matt's 1200psi regs. I notice when the bottle sits it leaks down, all the way if I let it sit long enough. I changed out the seal between the reg and bottle and still I have the same problem. I have tried storing the bottle connected to the remote line and even disconnected but no different. The problem is sometimes intermittent, where I get no problems for a week or so.

I think you are right Roald. With the higher pressures these regs don't seem to be seating consistantly. I know Pat J had a problem with his 1200psi reg leaking by and blowing rupture disks. He got the reg replaced. I even blew a rupture disk after having the bottle filled on a hot day. It blew the low pressure side for some reason. It seems ambiant temps can play a factor on these regs, causing the springs, spring packs, and seals to expand and contract. These regs are also made of different metals, mostly stainless steel and some brass present. Different metals react differently under heat and cold.

It's just another reminder for us to be careful this these things.

Thanks Daniel, good feedback.
I had the LP side of one of mine leak up and blow disks as well, but it was an older kind
that used a coil spring.
Some of the tanks will leak form around the burst disc's, I get mine wet to rest them before
I install them now and find less problems. However, Wayne just mailed me and said that his
22 that I just got done modding is leaking / loosing air.
I've asked him to check the fill nipple. I'm betting it's just the valve, He'll put a few shots
through it and see if it stops leaking. If its not that I'll have to take a look at it for him.
I don't know how fast it's going down though.... lets wait and see. We'll have more info tomorrow.
Roald. 

The 850 Store

When I first put on a 1200psi tank a few months ago I had leaks at the gauge,a little tweaking and it never leaked again,I've used my 1400psi tank only by remote and no leaks that way,in fact the qb does 983 fps with this tank in .22(smokin).On the gauge I used permatex instead of teflon tape.This fall I'll probably put the 1400 on the 850,if it leaks it will be the valve or adapter but I'm betting it doesn't leak,hope not anyway,if it does I'll try it at a 2500 fill like you stated.