Absolutely none, with the qualification that I'm only talking about the Thunderbeast CB mounts, which use big triangular shoulder--huge amount of surface area compared to a flat barrel shoulder. Wipe the carbon off the mating surfaces and they go back to the same POI every time. A few other companies use this design, too, I think.
I've noticed that mounts that lock or ratchet do not seem to be consistent enough for serious shooting; probably better off using direct thread on those styles.
The group on paper is a 20.5" #2 7-08 with a 5" can (100yards); the group on steel is a 20" Remington sporter profile 35 Whelen with a 7" can (730 yards). Both are benchmark barrels. Point of the pictures is that fairly light barrels with suppressors can still shoot lights out. At least for shorter strings.
