A buddy of mine and I did a trip PD hunting in Montana years ago. He was working up a load for his new .220 Swift. He was using one of those polymer tipped Hornady bullets. At a certain point, his accuracy went to crap.
He calls Hornady. "Yeah, I get it to (I forget the speed - 4200fps???) and there are no signs of pressure but the accuracy drops off and I'm key holing a few shots."
"Yeah, at that speed, you're driving the polymer tip into the bullet, messing up your aerodynamics. Back it off under 4,000 and you'll be fine. That's the top end."
I suspect 22K in a 55gr bullet would do similar. Resistance increases exponentially.