You're probably right but remember that the scope and barrel usually move independently of each other as the harmonic's do their thing. The barrel can be on an upward swing while the scope, which is attached to a different "node" can be on the way down.
Looks to me like you have enough clearance but as always, it pays to check. Put something on the bottom of the cap that will transfer to the barrel if it does hit then check after a few shots. Doesn't cost anything and it does prove that nothings contacting rather than still wondering.
