The cars and trucks I've purchased all came with a recommendation to run the vehicle at varying speeds for the first 500 miles to break in the engine.
My old Honda motorcycle came with instructions to keep the rpm's under 6,000 for the first few hundred miles - it redlined at 12,000.
Manufactured goods are built of pieces, each piece built to a dimensional tolerance range. Kahr, among others, likes to keep those dimensions close so the new parts fit together tightly. That is a large part of what gives them their exceptional accuracy. Shooting the pistol allows those parts to wear against each other in the exact perfect spots where they touch in that particular pistol. Those exact spots of contact might vary by a few fractions of a millimeter in another pistol whose parts are all just slightly different in their dimensions.
If a manufacturer tried to polish each piece perfectly before assembly they'd still be off a bit due to those minute dimensional differences. Wearing the actual parts where they actually fit together ensures that "perfect" fit.
A factory could wear in a car-motorcycle-handgun before selling it, but the cost would then have to be passed on to the consumer and folks would then complain that they aren't buying Brand XYZ because it costs so much more than ZYX - particularly when brand XYZ has obvious wear patterns on it right out of the box!
