You may want to buy a new gun...believe me, I've been there. But this seems to make the most sense to me:
If you've been comfortable with the 12 all these years, keep it. Practice with light target or skeet loads (buy em, or better yet make your own to suit your needs) and load it up full bore for home defense. Light loads in a full-size 12 gauge will be the mildest combination possible. Should you have to use it in a defensive situation you won't feel the recoil...and you'll have the most effective amount of lead going down range.
Changing from the 870 platform that you're familiar with to another brand may not be a good idea should it be needed in a stressful situation. Also, going to a smaller (and lighter) 20 gauge shotgun may just result in the same, or more, felt recoil on the shoulder...and less lead on target, everyone loses.
If you've been comfortable with the 12 all these years, keep it. Practice with light target or skeet loads (buy em, or better yet make your own to suit your needs) and load it up full bore for home defense. Light loads in a full-size 12 gauge will be the mildest combination possible. Should you have to use it in a defensive situation you won't feel the recoil...and you'll have the most effective amount of lead going down range.
Changing from the 870 platform that you're familiar with to another brand may not be a good idea should it be needed in a stressful situation. Also, going to a smaller (and lighter) 20 gauge shotgun may just result in the same, or more, felt recoil on the shoulder...and less lead on target, everyone loses.