I have a slow leak in my Hortitsia. After I air it up to 250 BAR and shoot it, I re-air it to 250 BAR and leave it in the safe for a few days. When I get it out to shoot it again it has leaked down to around 150BAR and holds steady. I have done a soapy water test around the fill port and air gauge, but no bubbles. Does anyone know where else I could check? I have had the barrel out of it and did a soapy water check on the air tank. No joy.