Rifle Scopes How close is too close?

[Nolo Contendere]

Mounted a scope this weekend - it's extremely close to the barrel. I can slide a piece of copy paper between the scope & barrel but can't slide a business card in there.
Also the BC obj lens cap touches the barrel. I can slide the scope back to get a little more clearance if I have to...

 

[TRAAV]

Thats to close. even without the cap on it would be closer than I would like. Im not sure how much but the barrel will flex under recoil

 

[tomcat mv]

Just my rough rule of thumb, but I I like at least an 1/8".