TXFRNTLDER
3-in-1 is a good oil if used for what it was intended for a short period of time. I would not use it for anything long term and I really do not think I would use it in a bore unless that was the only alternative. The biggest problem I have with it is it tends to draw, catch dust and lint...
You are really better off using a quality gun oil. There is a ton of them on the market... the military is pretty hung up on Break Free CLP. A lot of people here useBirch Wood Casey Sheath which now is called Barricade. And certainly other products designed for fireams will work... I am going to try another product here shortly, again a military product that is being used.
http://www.slip2000.com/
Have no idea of its abilities but want to give it a try - I like the thought of a natural product - I think....