Locked Breech vs. Blowback

It's better for a semiauto pistol to have a locked-breech design
(rather than direct or delayed blowback), for both reliability and safety.
If the breech is not in fully-closed "battery", with the firing pin close enough to the
primer, the gun might not fire; and if it does fire without battery, that is dangerous.
A locked-breech pistol can indicate a problem before you attempt to fire.

In physical struggle with a perp, a locked breech will reduce the chance of the firing pin
moving away from the primer due to slide contact with a holster, pocket, or perp.
(shooting from a holster/pocket can save you)

A locked breech also gives the bullet more time to exit the barrel,
and for the chamber pressure to drop, before the breech opens.
A 22magnum revolver is a powerful and reliable choice for those who want simple safety.

http://en.wikipedia.org/wiki/Headspace_(firearms)

"Dry Firing"

Dry firing an unloaded gun without a "snap cap" to take the impact
can deform the areas that stop the firing pin (or striker).
When in doubt, assume that you should not dry fire.
(you should have a colored "snap cap" when shopping for a gun)

If you have no "snap cap", you can take a fired casing and apply
a flexible material over the fired primer, or into the primer well.
(neoprene adhesive or tape works)
.

Some CC Needs

-- Gun should be small enough and light enough for hot humid days,
. . with light ordinary clothing, and for daily carry up to 16 hours.
. . (A "fanny pack" is one option that works with the larger small guns.)
-- Quick one-hand access with accurate first shot that can penetrate
. . auto door glass or a ribcage at ten yards. (little bullet yaw)

-- At least five shots without malfunction, plus loaded mag or revolver speedloader.
-- Indication that the gun is empty, providing some time to evade or reload, or to
. close the slide and bluff. . (slide locks back, or indicator, or last-chamber mark)

-- A semi that almost any adult can rack with wet, cold, and maybe dirty hands.
. . This can be a big hurdle. .I've had to make careful mods for my wife.
-- Rifled length ("barrel length" minus case length) at least 6 x bullet diameter.
. . . (for muzzle velocity, low yaw, aiming) . . This can also be difficult to meet.
. Barrel length is from breach face to muzzle; sometimes less than overall length.
. For 38acp(.36"), "barrel length" must be 2.85" to have a rifled length of 2.16".

-- The "6 x rifled length" is not in stone. I just accumulated indications of yaw
. . reports for various guns, some principles of short range stability, and range
. . tests with my Keltec p-32 to arrive a spec that seems to assure that a bullet
. . will arrive point-first at a barrier within 10 yards before entering soft tissues.
. . Many small guns have shorter barrels, but I would not buy one myself.

-- Avoid hollow/soft points in 17mag, 22mag, 25acp, 32acp . (avoid 25acp whatever)
-- Need range reliability testing for at least 30 rounds after functional corrective work.
.