Here is some info from a post I made on "another" forum on the Series 2 safety.
Brief History:
The Swartz safety was patented by Colt in 1938 and was intended to go into the Colt 1911's. I have never heard a reason why Colt did this back then other than they thought it was a safety improvement. From what I've read, the fitting of the safety was an additional step in their manufacturing and when they got the huge order from Uncle Sam in 1941, they just did without it.
The System:
The whole system consists of a push rod on the sear pin, a plunger in the slide, and a spring on top of the plunger that is held in place by the rear sight. The push rod is activated by the grip safety and if installed properly by Kimber will begin to push the rod up as soon as its off the trigger bow. Most of the reported failure to fire problems seem to occur when there is a "dead spot" between the trigger bow and the bottom of the push rod. The push rod is activated by the extended part of the lever of the GS while the trigger bow is blocked by the cut out part.
Its considered a good engineering design because it didn't require the shooter to do anything other than he/she normally did and did not affect the feel of the gun. The amount of upward force on the push rod is tremendous considering the area difference of the grip safety and the cross section of the push rod. BTW, this is why a "grip of death" as we have heard it called will do no better than a "grip of pushed in all the way".
Disabling: You can simply leave all the parts of the safety in the gun and disable its function by replacing the Kimber firing pin with a Series 70 type firing pin. There is no notch in the rear fat part of the pin to allow the block to engage it. The plunger will rub on the fat part of the new pin but the spring is weak. I have not heard of or seen a post on any forum where anyone reported any damage from doing this.
Removing parts:
To remove parts (to make sure they are gone, I guess), you must remove the plunger. Drift off the rear sight, be careful because the spring will want to bend when the sight passes over it. Take out the spring and plunger. This will leave a hole in the bottom of the slide. As best I can see, two things can happen here (one bad) but I haven't tried it so its speculation. The open hole will be a nice place to collect dirt and grime. The only harm is a dirty sight bottom I guess. The other thing to consider is if the push rod can get stuck in the hole where the plunger was. Again, if manufactured and installed per design it shouldn't be a problem since the rod should not extend that far. If I were going to do this, I think I would first measure the full rod extension and compare that to the clearance from where the slide sits on the frame to the bottom of the plunger hole.
Removing the push rod and not the plunger will assure that the gun will not fire..........DOH. If you remove the plunger, there is no reason to keep the push rod. You can take it off the sear pin. As far as I can tell, the slide has a milled relief for the push rod so it doesn't change anything as far as the sear knows. The sear will stay in place by the disconnector. This will leave another open hole in the frame. This one can channel dirt and grime down right to the sear........not a good thing.
Most of the problems you hear about are failure to go boom. The hammer drops but the firing pin is still blocked. Its usually due to the bottom of the grip safety not being fully pushed in and the push rod not extending far enough to engage the plunger. I have two Series 2 Kimbers with thousands of rounds through them and never had a problem.
