OCD1,

For reloading for your AR-type semi auto rifle go with full-length resizing. Don't even think about neck-sizing only for the AR. The real value of a case inspection gauge is in detecting over or under-sized cases and thereby preventing headspace issues. Remember, the range of acceptable versus excessive headspace is only 0.005" of so. Too small to detect by eyeball, but enough to detect by touch across the casehead when in a gauge.

Bolt actions can get by using neck-sizing only because they have a lot of mechanical advantage (cams) in forcing a bolt closed on a slightly oversized case. AR rifles do not.

Many, if not all, of the AR kah-BOOM! incidents involve cartridges that are undercharged (squib loads) that leave a bore obstruction and the following full-charge load destroys the rifle. The military has studied kah-BOOM incidents using the M16 series service rifles and squad automatic weapons and and have rarely found ammunition-caused failures. What they have found show that many gun blowups are caused by operator error: attempting to chamber and fire bent cartridges, dented cartridges, loose bullets, extremely dirty chambers, etc that cause firing out of battery.

You can avoid most of these problems simply by maintaining high inspection standards and paying absolute attention to the reloading process. I, and many of my shooting friends, avoid high-volume production progressive machines for this reason. We have seen too many instances of under-charged and over-charged cartridges that have come from using progressive reloaders.