O-ring 23,0x2,5 NBR 70 description this is off of a fx wildcat skematic

It appears that you may be asking about the filler end housing O-RIng?

Attached is a Gen I Wildcat O-RIng order form along with schematic and parts list....

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View attachment 1574829522_1018613245dddfdd2280ac2.41695216_FX Wildcat O-Rings 2019-05-29.xlsx

Hope this helps!

mike
 
Nope revoman its the other with the regulator what is happening is i have a leak through that little pin hole hoping i can take off the air tube and leave the air gauge and fill port alone just take out the end with the reg it should be leaking from # E4 which on the schematic appears to be the o rings that are on the air regulator adapter housing. Did you have this problem before ? I was going to pull it apart today and try to check the size with my dial calibers but once you take an o'ring off it could be stretched .
 
BBB- dimensions given on the FX parts diagram for O rings are cross section size, then ID. Go to oringsandmore. Scroll to the metric buna70 section and pick out all the o rings required for this gun, as I did. There are I believe two o rings that are Buna90, so watch for those. I believe yours is an MK2? FX website has the parts diagram for you to download. 

Regulator o rings for the MK2 with AMP regulator size is 23.3mm ID x 2.4mm thickness(cross section). I know, the commas instead of the periods thru me off, also.

The hydraulics store.com has dowty seals which you’ll need, as the wildcat has two of them, an M7 and an M12. The M12 is the one at the rear of the air tube, and depending how hard you re tighten your air tube back on(sheet metal workers grip, I know) you could easily cause that seal to leak. Mine was leaking just the other day, I found, from over tightening it to adjust the fill probe hole to my liking. Glad I had the spares.

Lastly, there are two o ring sizes not given- the o ring on the valve seat and the one on the valve stem. I’ll get that to you in a bit.

Total cost for o rings will be around $15, and you’ll have enough to re seal your entire gun 50 times, lol. 

Or, if you wanna go the simple route and not have to pick o rings off of the parts diagram, Captain o rings has a pre put together kit with enough o rings to reseal your entire gun twice. I believe it’s around $35 for the kit, and you can download a location diagram as to where the o rings go on the gun. No dowty seals are included in their kit.
 
coma is actually a period that was confusing air was leaking from that little pin hole in the back maybe 50 psi a day so i figured i would take it apart and fix it then today i was doing a little shooting and the o'ring in the back of the barrel blew out so i pulled the barrel and it blew out again so i figured it stretched what a bummer but i think i caused it maybe i cranked up the hammer spring about a full turn approx. got it shooting 30,8 FPE its like a rocket i did that about 100 or 200 shots ago so that might be my problem but it smacks them squirrels hard I have a mark 1