Does anyone know why some Ruger Wranglers keyhole?

My guess would be since they make them to be convertible between 22lr and 22WMR, that the barrels are sized for the 22wmr, which is actually a little larger.  So if you get undersized 22lr, they don't stabilize correctly and end up keyholing.

Wranglers aren't convertible between mag an lr but Super Wranglers are.  

My Wrangler is lr only and keyholes like crazy after it heats up.

I guess my next question would be what is the twist rate on it, and what ammo are you shooting?  Have you tried standard velocity ammo, or are you shooting high velocity?  It is amazing the difference ammunition, especially 22lr, can make.  I had a gun that was a jam-o-matic with one, but never had a misfeed with another.

My Wrangler will keyhole with CCI Quiet solids.  Quiet hollow points don't keyhole, but they pattern rather than group.  Move up to standard velocity or high velocity ammo and it shoots better than I can hold these days. Those sights were not meant for bad eyes.

From my understanding, the barrels are 1:14 twist, whereas Ruger 10/22 barrels are 1:16. The twist will have an effect from bullet weight and velocity of that ammo. You'll need to try different ammos' to see how it reacts to the target (keyhole or smooth round punch) and keeping the distance to target within a range of about 10yds and less.

I have heard of a tuner that has worked on the barrel's muzzle to clean/square up the rifling end to make for a better shooter. I believe he did a target end grind. There's a video online of him doing customizing of the whole gun, taking out all the mill work fancy-ing up the gun, gave him a better shooter from what I gather.

Over on the Ruger site, guys have said these Wrangler's will shoot shorts and long, along with long-rifle just fine.

Generally the cheap bulk stuff.  Remington and Federal.

If you have a bore scope, take a peek at the rifling. If it looks good, send it to the Mothership. I've never had a .22 keyhole with any load

I had one that keyholed. I sent it back to Ruger and they sent me a new Wrangler. I figured they would simply replace the barrel. The replacement Wrangler seems to shoot well, without keyholing.