[Drakker]

As far as I know no one ever postulated that strong hops would deform the BB (but alas, I don't know every hypothesis out there). That is quite an interesting idea. Also, the quality of the barrel might play a part here, as a smoother, high quality finish barrel is less likely to scratch the BB, again affecting accuracy.

This would be quite simple to test, fire say in a pool from far away so make sure that no impact deforms or scratches it, and check the BB with the most accurate measuring tool you have access to and a microscope to check for scratches.

Considering the BB rides on top of the barrel, and that it will still pick up spin from contacting the surface, which is what LRB (slightly curved down barrels) used to exploit, if the BB is not spinning around it's center mass, it's going to hit the ceiling of the barrel erratically, and any defect in the barrel means even more erratic path inside the barrel, which results in lower accuracy with a regular hop, but not as bad of a loss with a flatter hop.

Also, people have speculated that when the BB stabilizes to spin around its center mass, it is actually bleeding energy and it reduces the spin rate faster, affecting the magnus effect at range, which directly affects how far the BB will fly.