1911 Break-In period
This is a great topic and I will cut straight to my opinion, yes and no. The reason for so many companies claiming a need for a break-in period is because they are not built right to begin with, and instead of correcting them, the hope is that the gun will eventually "wear-in". This is when NO is the right answer. Many of the 1911 companies who shoot for a tight fit, do so through friction instead of tolerance... if it feels tight it is tight mentality. You see this manifest on the frames rails, barrel muzzle end, breechfaces, lower barrel lugs, slide stop pins, high/low spots become very apparent where tightness is a result of friction on high spots. As these high spots wear, and they will do so at a faster rate, the gun will loose this artificial tightness.
Tightness from friction is not the same as tightness through tolerance. Tightness from tolerance is numerical, it implies that two perfectly parallel, two perfectly straight bearing surfaces are mated together with very little distance between them... 0.0003" to 0.0005" tolerances is what I consider perfect between critical bearing surfaces. This allows oil to work without any up/down or side/side movement of parts. With that being said, I would sacrifice a little bit of tolerance to ensure the bearing surfaces are parallel, square, straight, etc. If you lap the slide raceways with a parallel lapping bar and then surface grind the frame rails, you get very nice bearing surfaces which last a long time.
Barrel fitting also causes HUGE friction points. Hood fit, lower lugs, bushing fit, all major friction points. I am not a believer in a hood that "snaps" in and out due to friction. You want a close to zero tolerance, but the hood should slip in and out of position, the hood absolutely needs to be square with the breechface or again, the high spot will wear quickly and you will loose the tolerance. Lower lugs should also slip into position on top of the slide stop pin, it should not require a great amount of force in or out of battery, or it will wear the slide stop pin and/or lower lugs and you will deform these parts, loosing fit over time. Bushing fit can be another huge friction point. I currently OD grind the muzzle of the barrel to ensure the barrel is concentric. I am a firm believer in a reduced bearing surface at the muzzle to ensure proper tilting of the barrel without springing and reducing friction points so the bushing does not pull the barrel forward before the hood contacts the breechface, one of the reasons for my Radial Bore .
Friction is not your friend, close numerical tolerances IS a friend of precision pistols. You want to eliminate friction while maintaining close tolerances to ensure accuracy, proper operation, and long life. SOMETIMES a well built gun will get a specialized coating like hard chrome or PVD, and a 0.0004"tolerance turns into a 0.0002" tolerance, slowing things down a bit. THIS is when a properly built gun may need a break-in period. Most cases the builder will do most of this break-in period before shipping the gun. A gun that you have to beat in and out of battery, is not built right. This is my opinion and and the main reason I machine/grind all critical bearing surfaces.