Erik Asks: I've been seriously training for roughly a year with best lifts of 100/123 as a 94. My question is this, I often find my grip on the bar changes during the clean during the lift so that my hands are uneven, and this only gets worse when I receive the bar in lower positions. I'm able to rack the bar with a closed hand so I do not think it’s a mobility issue, rather an issue with the execution of the lift?

Greg Says: This isn’t too uncommon, and it’s definitely originating in the execution of the lift itself, not in your ability or lack thereof to establish a solid rack position.
 
I would argue it’s not an issue of the receiving position getting lower, but of the weight getting heavier, which changes the way you approach the lift mentally and then that influences its execution. Simply, you’re in a rush to get under the bar because you’re less confident that the same motion will work with heavier weights, and this rush results in losing connection to the bar during the turnover.
 
The only way your hands can move on the bar during the clean is if your grip is loosened before the bar is resting on your shoulders. The solution, then, is to make sure you’re keeping a tight enough grip on the bar through turnover until your elbows are coming up in front of the bar.
 
In order to be able to do this, you need two things: a strong enough upward drive in the pull to get adequate speed and elevation of the bar, and a quick enough turnover, which demands the movement be executed properly. Namely, the bar needs to remain close to the body and the bar and shoulders brought close together with a pull of the arms prior to the elbows actually moving around the bar. The elbows then need to pivot around the bar—actually spin it—to move into position. If the turnover is done correctly, the hands never need to spin on the bar, which means the grip can remain tight throughout the entire motion.
 
Practice the turnover in isolation with tall muscle cleans and tall cleans. Focus on maintaining your grip throughout the turnover and spinning the elbows around the bar as quickly as possible. From there, work to cleans from power position or high-hang cleans to practice an aggressive upward finish feeding into that perfect turnover.