TOM: I have to disagree somewhat with your condemnation of the Thompson Contender's in 223 Remington.
I have two friends that bought those 25+ years ago and I watched them shoot Colony Varmints (Rock Chucks and Prairie Dogs) with their 223's out to amazing distances (300+ yards on occasion!).
I was so impressed with their performances that I went way out of my norm and bought myself a T/C Contender pistol in 223 Remington with a 14" heavy barrel and a Burris 3x9 pistol scope for it.
I was amazed at how well it and "I" could shoot with that rig.
Admittedly this is a somewhat small "test group" but all three of these T/C 223's shoot so very well.
This T/C is the only one I have ever owned but I am sure thrilled with it.
It took me a while to "adjust" myself to being able to find Colony Varmints in the smallish field of view of the Burris scope but I learned.
I use good quality ear protection when I shoot my T/C - no problemo. If I am shooting prone it WILL kick up some dust as well - but again livable for me.

So for the original poster (Nathan 30) I do NOT wish to talk him out of a 20 caliber Contender - in fact if the 20's had been available (and the reloading components) back then I may have chosen one of them.
Hold into the wind
VarmintGuy