That sounds like a poorly tuned (specifically, over-gassed) gun. This is more common then not as manufacturers often use excessively large gas ports to make up for crappy ammo with low or inconsistent pressure. However, ARs should never have harder recoil impulses then guns of like caliber and non reciprocating actions; physics just doesn't allow for it.Every once in a while I get the bug to do more stuff with ARs. Doesn't take long to remember why I like bolt guns. The recoil impulse, the noise (especially with a can), the way they trash brass, gas in the face, and general handling characteristics while hunting with an AR not attractive.
The first time I shot a well-tuned JP rifle, it was eye opening how different it was than the rack grade Colt I'd used prior. When you get that rifle dialed in with the right combination of buffer weight, spring, gas block, and gas port, to say nothing of a good muzzle device, it's almost surreal how gentle the recoil is.