Hi, and welcome.

I’m familiar with the internals of the Strongarm/Disruptor. The Eaglepoint operates in a very similar way so I’m going to assume that it has similar internals. There’s a small spring-driven nub which interfaces with a cam; pulling back the plunger pulls back the nub and firing allows the nub to spring forwards (but on its own spring, so slower than the plunger tube). The cam then drives the cylinder, resulting in the cylinder spinning just after each dart fires.

It’s possible (indeed, in the very long term likely) for that cam to wear out and for the cylinder to rotate unreliably - but this leads to failure to spin, not spinning with the wrong timing.

It’s more likely IMO that you’re seeing darts not leaving the barrel fully. Try holding the cylinder in place with your hand while you fire - does the dart still not leave the cylinder properly?

This may be caused by having old and worn-out darts, or darts which have been stored loaded (which compresses the foam; hot air can perks them back up). It may also be caused by the darts not being fully inserted.

How old is your son, by the way? “Kinda disappointing” describes many of the blasters in the Elite 2.0 line as Hasbro was going through a severe cost-cutting period at the time. I can make some recommendations if you’re looking to expand the household arsenal, if you’d like, and it helps to have an idea of what age I’m recommending for.