Philosophical Differences

What to use to defend yourself?  It's not a simple question.

We carry handguns about in public because most of us are forced by law or social convention to hide them from view.  Even the staunch open carriers carry a handgun because it's small and light.

There's a great deal of truth to the statement, "you use a pistol to fight your way to your rifle."  Handguns are underpowered compared to just about any rifle.  Even the vaunted .44 Magnum is not bringing as much energy to the fight as the maligned .223.

Shotguns are fowling pieces.  That they are used for other purposes is a matter of law not prowess.  If you are choosing a shotgun for home defense and cite over-penetration by a rifle; see this link.  This link too.  00 Buck is nine .36" round balls running about 1,300 fps. each.  Combined it's quite a load, individually not so much.  They conspire to be about the same damage as .223 or 7.62x39.

Pistol caliber carbines are really big pistols and not small rifles.  Yes, the extra barrel length might boost a 9x19mm round's velocity to .357 magnum speeds; but .357 is still what?  Yes, a pistol round.  Cruise through that box-o-truth site and you're going to notice that you're not solving the over-penetration problem here either.

What are you gaining when you eschew the rifle?

Cost has been trotted out.

If you're able to afford a $500 Glock, you're also able to afford a $300 SKS.  A $400 Kel-Tec is still $100 more than a $300 SKS.  A $300 SKS is the same as a $300 Mossberg.

And they are all cheaper than a $1,200 Colt AR.  But there are much cheaper examples of AR out there, hit up the pawn shops for examples.  A Century M16A1 kit-bash refurb will be in the $500 range.  It's not in a stylish tacticool configuration, but it's going to work.

Update:  To show the relative bulk; and the stratospheric price of a well equipped AR.

Remington 870 with light, Magpul furniture, extended magazine and Sage sights.  10 lb. $750.  7+1 shots.
Laconic Arms AR-15 with light, Magpul furniture and EOTech.  8.7 lb. $1,822. 30+1 shots.
S&W Sigma SW40F.  2 lb. $500. 15+1 shots.

The same $750 that bought the shotgun also bought this M16A2 clone.  8.2 lb.  30+1 shots.  I've seen AR's in this configuration going for less if you're willing to accept some cosmetic dings and that it's not in a stylish configuration, like the carbine shown above.

Update 2: "What you've made with your shotgun is a long arm as handy as an M1 Garand with 1/10th the range with ammo that weighs twice as much."  Thanks for the perspective, Willard!