It's my preferred light oil. I don't much think any single product is a cleaner, lube and protector in the full meaning of those words. It's certainly true that Weapon Shield is a claimed improvement on FP10 and I suppose it is - there's some history there and it's all available. I am content to continue with FP10 if that's what comes to hand first.
To sum up I believe Weapon Shield is as good as it gets for light oil. That said I like lots of other products for lots of other purposes.
+1 to Clark's post. I ordered a quart of the stuff several years ago and think very highly of it. I did the same with the original FP-10 before that, so I've still got quite a lot of both on hand. I personally prefer Weapon Shield most of the time because its a little thicker which usually suits my needs better, but I was completely happy with FP-10 before that.
I'm kind of a lube nut too, and own several. For a do-all CLP I think Weapon Shield is a very good product.
