Might be able to help. I've got a special covering for the end of the barrel. Made by a company called "Trojan", it may not help with "ejaculation", even with the "shell catcher tip", but will keep foreign matter and moisture out.

By the time you get it into your back yard, will you have a house, or lean-to?

I can imagine your basic German village being real happy to see these things at 11.5 feet wide come rolling into town to "protect" them. It might have to push small buildings aside with it's barrel in order to turn corners, raise it to turn others, tearing out wires in the process, and whatever part of the roadway it didn't shred it's support vehicle would finish off. In the summer. Might sink out of sight in the Fall and Spring.

Or, you could airlift a 155 howitzer into place.

Good luck with the thing. It'll be a hell of a drawing card for the kids lemonade stand.

Arf