Yes, just gravity, two machined surfaces with a small gear on the body driving the large ring gear on the turret. Yeah, no displacement of the turret and body machined surfaces through all the violent motions they go through. And, though I don't understand the dynamics of it, even with the violent motions these machines go through, the turret wasn't beating the machined surfaces to death, nor would they fall off unless overturned. The Soviet tank barrel has no lands and grooves to spin the projectile. Spinning a projectile is what it make's it stable; a non-spun round wobble's, so is not very accurate, but the high gain it makes in velocity by not having lands and grooves for the combustion gasses to leak around and ahead, slowing it. And, yes, only the kinetic energy from the Soviet round could knock the turret off of an M60. Though this is only an academic point, the Soviet round is ladened with explosive charge. As an aside, the American land&groove barrel, very accurate, but lacking kinetic energy versus the smooth-bore Soviet barrel, inaccurate with incredible kinetic energy, in my opinion, led the Soviet war planner's to wish for a close-in tank war where they had the advantage. Modern "active-armor", where underneath the first layer of high-strength steel of armor plate is a layer of fast-burn explosive. So, when a projectile, of whatever type, strikes it sets off the charge causing the incoming projectile to explode prematurely, alleviating much damage. Tank-killer airplanes, cruise missiles and the like make all this moot. Plus, the American's new Abrams which can move and shoot with incredible accuracy leave's no world counter-part to challenge it.