Well, 8200 rpm.
At conversation as in 7-21 feet I would have to say first off .45 ACP handgun with Hydro Shock, Golden Sabres or simular.
Now given the choices, Shotgun or lever action...I as well will say shotgun and rember to aim!!!!
At 25 feet, the pattern will be about a 1.5-2 inch group....not a spray and waste like some think.
I will also say, for a HD gun that minimal is #4 buck with 34 BB's
to 00 Buck with 12 BB's.
Reason being, you miss....#4 buck will slow down very fast when going through drywall and studs. 00 Buck has less BB's should you miss........
Remember to aim....What I would say is find some place in your area that does Pin shoots. Yes bowling pin's at 25 feet and get humbled. Find out that a shot gun is not spray and pray...One Must Aim....GrassHopper.
Now an AR is also great but I feel over penation may be a bigger factor..If you miss at 25 feet to 50 yards...where did that little 55-62 grain bullet go
Flying at 2700+ FPS......Geez was Mister Roger's in his living room
Go to the range, practice and remember FRONT SIGHT and test your self, push yourself and make every round count.
I can do 5 pins in 4.2 seconds with a pump gun and #4 buck.
Practice, and remember front sight.
Just my opinion
Karsten