Are you travelling with the marker or sending it to someone ?
I would say sending it broken down and listing it as sports equipment (as it is actually classed by the US TSA) it should be fine. Even go as far as enclosing a printout of the TSA guidelines pertaining to transporting compressed air-weapons or paintball markers.
If you want to be doubly sure, email a retailer like Lips or BZ and ask if they have any customers from the US and what services they use to send internationally ?
At the moment I'm not sure, after what happened I asked the Tippmann tech I was talking too what my options were, he hasn't got back to me yet as its only been a few hours. I've got Tippmann parts from Belgium before but I'm not sure if they do the C3, it was only sold in the US (to my knowledge), if that matters.
Thats what I fear unfortunetly. I called up Just Paintball because its near me, they offer repairs and I knew 99% they couldn't do it, the guy on the phone didn't know what it was and started laughing when I explained it runs off Propane, lol.
I've asked Tippmann if theres anywhere in the UK that can do it, I suppose I'll have to wait and see. Thanks.
If anyone can do it in the UK then it will be the Tippmann tech at BZ
If you have to send it to the US then use the advice as above to be ready for TSA, there should be no other issues with it crossing borders and on return it should pass UK customs in regard to the VCRA or other legal importation issues
Include details of the warranty/service work when you send it, Tippmann should also include documentation on return
Keep a copy of any paperwork ready to send if it does get queried on return
(note usual customs VCRA queries are raised by the courier to you then they refer your response to customs as appropriate, eg I've imported via airsoft suppliers and been asked if its a RIF, it wasn't and the package had never been opened in transit as they accepted my declaration, (or possibly xrayed it), on other occasions packages have been inspected)
Make sure your email & phone details are documented when it's sent each way to potentially speed up queries)
What did you tell the post office?
Did you mention propane, or say the words 'paintball gun'
Also when asking at a desk you rely on them having the right leaflet or knowing the right guidance information