You could purchase a decent O/U Savage Mod.24,though they are single shot,& quite heavy,but in various combo calibers,including .223/.22 L.R. The mod.24's are not made anymore,& haven't been for more than 30yrs.New England Arms are the Newest choice here,they make O/U singles in just about every caliber out there,much lighter due to synthetic stocks/furniture,modern mfg. technique.The Ruger 10-22 is what I've used for squirrel hunting most of the time,& A Sears-Roebucks single shot in .22 gallery shorts in my post-toddler yrs. The .223 conversion to .22 LR is NOT practical,at the very least,The Ar-15 bore is designed for the .223 round which is 2 times longer in length than a .22 LR round,& are usually bored with a 1-9"twist,thats 1 complete revolution per 9" which will put a very tight spin on the much longer .223 giving it a Very flat Trajectory,well past 100yds.with Ball ammo.Don't waste your Money on the conversion!