I have read about 223 varmint bullets,ie, Hornady Varmint Max, Nosler, Barnes, Speer, all make varmint bullets . These are reported to very effective at close range.
Some say that they doubt the effectiveness of a frangible bullet on a Meth crazed intruder, I say if he takes all the energy from one Varmint Max, give him some more. These bullets will not penetrate much, but no penetration means no loss of energy going into interior walls.
I have a pistol for this purpose. It is much handier than a long gun and is kept, when the grandchildren aren't about, in a bedside drawer. When the little ones are about it's kept religiously under lock in a safe.
I bought my wife a Smith and Wesson MDL 642. A snub nosed 38SPL+p. She is a small business owner and has had some scares working on orders late at night. This is a very small pistol, hammerless, with enough power to make me back up, My wife loves it!
Consider all options, but realize that these situations, where you have to defend your family with deadly force is very traumatic and you have to be able to function under great stress and fear.
I like SAR's, but they are complicated when compared to a revolver. A revolver goes bang everytime you pull the trigger. No mags, no cycling a round into battery, no safety. the safety is behind the trigger. Whatever you chose good luck.