In essence it is the Taurus lock, but S&W ( despite being offered the use of Taurus patent locating the thing on the back of the hammer ) insisted on putting it into the frame. I imagine that was so someone couldn't swap the hammer out with a pre-lock hammer.
The Springfield lock of a similar nature can be added to any 1911 that takes a standard mainspring housing. OR THE LOCKING HOUSING REPLACED WITH WITH ANY STANDARD NON-LOCKING HOUSING. By placing it's lock in the frame S&W is making certain you don't have the option of removing it.
And yes, the lock ( per experience with Taurus ) can work itself on. Leaving you with an inoperable gun, til the key is inserted and turned. The "slickslide" S&W DA autos with frame mounted decockers have a flat circular plug replacing the safety lever on the slide. They have, I am told, rotated into a position locking things up.
Rifles and shotguns are used in an offensive role. You should know and have time to manipulate the safety under those conditions. The handgun is a defensive, a reactive tool. Usually under circumstances of already being behind and trying to catch up to the action.
In essence, the anti-gunners are trying to ensure that even if you have a gun, you don't have time to make it operable. It's also one more step down the road to an active smart technolgy weapon that can be disabled by radio signal if riots break out. One more step to insuring the busybodies who have no business sticking their noses into your lives don't suffer the locical consequences of their actions.
My philosophy regarding the camel sticking it's nose into your tent is to react by slapping a branding iron to it so it sees the relection of it's stupidity every time it looks down to take a drink.
One more point and then rant mood off. Col. Jeff Cooper, asked if violence did not beget more violence in essence said that was exactly his point, and that starting violence it would beget a whole lot more violence than the gun who started it had a stomach for.
