To me its not a matter of what I'm loaning, but who I'm loaning to
This is how I feel. There are only a few conditions that must be met for me to feel comfortable lending a firearm to someone.
1) I know them well and completely trust them to use and care for it properly
2) They agree from the start to replace or repair it should something go wrong
3) It is not a gun I currently need, have great sentimental attachment to, or is not readily replaceable if necessary.
Now granted, the only person I can think of off the top of my head that fulfills criteria #1 is my brother, but I would be perfectly willing to lend out my "unnecessary" guns to other close friends/family should they convince me of their ability to properly use and care for them.