G forces on the bottom of the high bar in a tap swing on uneven bars has been measured as 4-7G's. That's on a women's bar.
G forces on the tap of a rings swing for a dismount is higher if I remember as it is also can be for bar dismounts on the metal men's single rail.
For a female gymnast, we are talking anywhere from 320lbs of force to 840lbs of force. For males that would be anywhere from 480lbs of force to over half a ton of force.
Even Kipping pullups via CrossFit probably are about 1.5G's to 2.5G's of force being generated on the bottom. Butterfly kip being where more force is generated while the standard CF kip is probably just over a G.
I really am growing to dislike this debate. Arghh!