Wish to purchase this rifle for home defense, but need to know what features to look for in order to select best model number. For example, which newer accessorized models are unnecessary. Owners; what recurring problems, if any, have you experienced including those requiring a mail back to Ruger. I own 9mm semi’s & wish to stay with this caliber for availability. Any & all comments will be considered and appreciated. Thanks in advance to all responders!