I would never lend anybody my air rifles I value them to much. You just never know how well your mate is going to treat it.
I let people at the range try them out and that's as far as it goes, they know how fussy I am so they respect it, especially with me being near by. Seeing how some of them look after their guns, no way.
One fella at the range bought a brand new HW95, it was as they are, lovely to shoot deadly accurate and only the slightest of boings. He lent it to his mate, and when he got it back if was absolutely crap. We first thought the scope was cream crackered, replaced it with 2 others to no avail, it just wouldn't group. Cleaned the barrel, still hopeless, tried all the normal things, stock bolts everything, still hopeless.
I wanted to take it apart but as there was a lifetime warranty from the shop it went back there. After lots of hassle it went to Hull Cartridge. Apparently they are saying that the barrel has had what they believe to be WD40 inside it and corroded it. Also it has bean dieseling so badly, that they seals have melted. No signs of dieseling when we go it back from his mate.
So when I last spoke to him, they are going to fix it, but it will cost him.
That lesson has totally convinced me that nobody will ever borrow my rifles, not even my son. I bought him two of his own.
God only knows what his mate had done to it.