The thumb safety could be removed and the firearm safely used (Rule #1: muzzle direction is the primary safety on ANY firearm!) IF its shaft was not also the axle for the sear!
There are two other safeties present: the magazine disconnect and the blocking plunger to the hammer that is activated by the trigger pull, which is like the M&P striker fired models in function, not form.
The original 1911's did not have a thumb safety. I911 's can be used with the thumb safety removed as its axle is not used for any other moving part.
There are two other safeties present: the magazine disconnect and the blocking plunger to the hammer that is activated by the trigger pull, which is like the M&P striker fired models in function, not form.
The original 1911's did not have a thumb safety. I911 's can be used with the thumb safety removed as its axle is not used for any other moving part.