Air Arms Owners Club

Hi guys im new to the forum so ill appoligise for this being my first post ive recently bought an airarms s400 carbine and i noticed after a few days that is was down on power so i got a friend to put it on a chrono and the best i could get was 9.4ftlb now ive filled it a few time and noticed a leak coming from the antitamper screw so i think its been messed about with could anyone please tell me how to put this right as im new to pcp's and dont knkw what im doing or is there anyone close by that could service it for me

Welcome..tell us where you are living and maybe someone could help

Sorry im in nottingham

PCP' Rifles have Rubber or silicone O.rings One of the O'rings is leaking However, wile the rifle is apart it good practice to change all O' rings this makes sense.
As if one O'RING fails the rest may also fail, the rile needs a full service and you can get a full O'ring service kits from Bonds Guns, a lad on this forum will supply most parts for Air Arms rifles.

Now!, if the rifle has been messed with, or is indeed second hand and your unsure whats been done! too the rifle, and if you can't do the work yourself or remove the Anti Tamper..ect,,, It would be best to take the rifle to a gunsmith and get it sorted out properly, as when you get your S400 back it will reward you with years of service.

Did you overfill the S400 with to much air Pressure... ?

zippy wrote:PCP' Rifles have Rubber or silicone O.rings One of the O'rings is leaking

There isnt an o ring on/in the naughty screw Mick (I assume this is what the OP is referring too). What screw/cap is there on the anti tamper screw? If the A/T has been removed there should be one or possibly two grub screws in there. I can only think that a leak would occur if the threads were damaged. If this is the case you will probably need to replace the firing valve body. See Julian (bgaltd) if you need any parts.

Some more info is needed me thinks.

Geordie wrote:

zippy wrote:PCP' Rifles have Rubber or silicone O.rings One of the O'rings is leaking

There isnt an o ring on/in the naughty screw Mick (I assume this is what the OP is referring too). What screw/cap is there on the anti tamper screw? If the A/T has been removed there should be one or possibly two grub screws in there. I can only think that a leak would occur if the threads were damaged. If this is the case you will probably need to replace the firing valve body. See Julian (bgaltd) if you need any parts.

Some more info is needed me thinks.

Yer, I know Mate, He applied that the rifle was loosing power due to the loss of air... ???
If we had the rifle in front of us to see the problem, I could sort it..

Sorry for taking so long to reply the rifle is pre antitamper i believe its a 2007 model ive taken the top allen key screw out and there dont look like any damage to any threads but im no expert ill try sending it for a service and see if they can sort it out because if it has been messed about with i dont want to be held responsible for having a class 1 firearm in my house without an f.a.c thankyou all

Hi,

It wont be loosing pressure in the cylinder by leaking air from the venturi screw. The only time any air is passing this screw is the split second it takes to fire the pellet from the barrel. It's either leaking from the firing valve, one of the cylinder seals, the gauge and/or seals or from the filling valve. Pretty straight forward to change (no anti-tamper fitted) but you really need access to a chrono. Total cost when I did mine a couple of years ago was about £35. I suspect a dealer may charge more than the cost of buying the parts plus a Combro type chrono. Just a thought! If you don't know what an Allen key is then take it to a dealer unless someone near you can help.

Mark

sounds like the o ring between the bolt housing and transfer port.
sort the gun yourself mate, then you know its right
only sort out what needs sorting, thats my motto.
sort the leak (if you get stuck, shout up on here) then fill to 190 and do a full string ove rthe chrono, post figures on here in fps, thats where its at