Please don't do this...it isn't a good idea.I like this idea because if you chamber without the violence of racking one in, then you should not have to move that round to the practice ammo pile if you remove it from the gun.
While it can be done occasionally, doing it on a consistent basis with a 1911 will shorten the life of the extractor...this would be regardless of the quality of the extractor. The 1911 was designed for the round to be controlled from the magazine into the chamber by having the rim feed up under the extractor hook as the round is stripped from the mag.
A former Marine shooting instructor related the story of how they went through a large number of extractors, in CQB training...both issued and aftermarket...during their failure to feed drills. Upon inspection by their team armorer, the cause was traced back to allowing the extractor hook to snap over the rim of a chambered cartridge.
They still practiced their failure drills, but they henceforth changed out their extractors after training and before carrying their pistols into action.