Re: 22WMR vs. 22LR as a trainer??
It's not a little more, unless you're talking about match ammo.
You can reload .223 as cheaply as you can shoot .22WMR.
Additionally, few mags give the accuracy of .22LRs.
You'll shoot a lot more with .22LR, and that's what training is all about: trigger time.
You get better wind doping experience from LR, less noise, and, depending on where you shoot, the ability to use ranges where hotter rounds aren't permitted (I'm thinking about folks who have to shoot indoors in winter).
There are competitions for .22LR: Silhouette, .22 Tactical, etc.
The only benefit of .22WMR is in the role for which it was originally intended: small game/light varminting out to 150yd or so, where the flatter trajectory and higher energy is a factor.
Where energy is no longer important, the LR shines.
At known ranges, trajectory is unimportant, so even shooting to 100yd (or farther, sometimes MUCH farther) is a reality.
Sinceyou already have the mag, you;ll have to balancethe price of a new gun against the few thousand rounds of ammo you can get for the same money,