The newly updated Mossberg SA-20 Field/Tactical autoloader is a 20 gauge shotgun with a 20″ barrel, synthetic stock and a variety of features that might make it a good home defense gun for you.  With the updated version shown at the 2013 SHOT Show, I immediately saw the gun’s home defense potential for a variety of reasons, not the least of which is reduced recoil.
The semi-auto action tends to absorb some of the recoil in the mechanical process of moving the bolt, extracting a spent shell and chambering a new one. Â Combine that with the lower recoil of a 20 gauge compared to a 12 gauge, and one can see how this gun will likely be more tolerable to someone who is more recoil sensitive. Â I’ve never had a problem training people of all sizes to shoot a 12 gauge, but a semi-auto 20 is simply easier for some people to control.