If buying used, Erich's recommendations are right on. If buying new, I'd personally choose a 20 ga/20 ga for the shotgun barrels, just because they are slimmer and good 20 ga ammo matches the performance of 16 ga. and is more available in the stores. I really like 16 ga. guns and own several, but they are not entirely practical any more unless you are an enthusiast and reload your own shells. 12 ga. drillings are just too large and bulky to handle for me, you may feel differently. Check the fit of a drilling before you buy. Stock fit for ideal shotgun shooting is a bit different than it is for rifle shooting. What compromise you prefer is up to you.
