Welcome to the forums, Furst.
As far as gunnery forces are concerned, it depends on the simulator model and aircraft/weapon types.
In CFS3, airframe models, especially the 1% models were very accurate in showing effects of weapons as they would have occurred (depending of the aircraft and it's armament). For example, P-39 firing it's .50 caliber MG had a noticable shake but the 37mm cannon rocked the pilot. Firing the Me262's MK108 cannon created plenty of shake, as well.
IL-2 Sturmovik is pretty accurate as well, especially with the Me262A1/U4, which when fired not only effected forward airspeed, but also a blinding flash.
These are just a few examples, but like I said, the "shake" created by the weapons are directly relevent to the aircraft type, weapon configuration and most importanly, the accuracy of the sim's modeling team.