If you are truly concerned about a gun being able to take that level of use, perhaps you should look into one of Tony Galazan's RBL doubles. He certainly stands behind them. The design is about as bullet proof as a double gets.
All the guns listed above can and do fail, but, nobody will stand behind them, save Galazan.
I seem to recall reading here that a few model 21s failed every year at one of the Vintager shoots. There exists a well documented problem with the soldering of the 4140 barrels in early model 21s. That type of steel is notorious for being difficult to wet in soldering operations. All the 21 guys poo-poo the problem, but, it is an expensive fix to re-attach a rib or lug on a 21.
Best,
Ted
