The thing is, I can't find any explanation to what the difference is.
I guess I'll ask at the gun store the next time I go there, if I can remember.
My guess is, the trigger disconnect means that if you pull the trigger, nothing happens. But the firing pin block, if you pull the trigger you get a click as the hammer falls, but the firing pin doesn't/can't strike the primer of the chambered round.
Sometimes there are both. I think the latest do up (Like from 1970? 1980?) of Colt 1911s doesn this.
I can understand why you'd want the first and not the second. If you hear a click when you expect a bang you have a problem you have to diagnose. It could be you left the safety on, or it could be a lot of other things might be amiss. It could be unloaded/empty with the slide forward, no round in the chamber, a dud round, a broken firing pin, and other possibilities other than simply an engaged safety.Better to know why it isn't working, and if there is no click when you pull the trigger and you have a trigger-disconnect safety you have fewer things you need to consider. The hammer is already down on your 1911, or the safety is engaged.
My pump action .22 rifle is a firing pin block safety. You can pull the trigger, the hammer falls ~click~, and if the safety is engaged nothing should happen.
And I bet Jeff Cooper had an even better reason/s to pick the first style over the second that I hope some reader would enlighten me with. Maybe the second style has inherent mechanical flaws that make it more prone to other failures. I don't know, but I would like to. And google hasn't been so helpful. Wikipedia has something that helps with the hammer/pin block, but not the trigger or sear disconnect.
I also know that many of the upgrades of the 1911 models (Series 80?) after WWII had something to do with the way the safety works and what happens when the pistol is dropped, but I don't know the differences there either. I am working on correcting that. I probably knew all this once, but the lesson didn't stick. I am a slow head.
There is even a chance, in my inexpert fumblings for info, that I have Cooper's preference BACKWARDS. How embarrassing, if true. Please correct my if I messed that up.
Here IS a direct quote from Cooper, but about rifles:
While I have certain reservations (along with my good friend and mentor Ian McFarlane of Okavango) about mechanical safety latches, it would be impossible to sell a rifle that did not include one. It should be operable with either hand. It should not extrude from the rifle to catch on things (as is the case with the Winchester three-position safety.) And it should disconnect the trigger and sear from the striker, while at the same time positively locking the striker. (People who count upon a safety latch to render a firearm inoperable are living in a dream world.)
Sounds like he means BOTH types of safeties, there, in one package...
Just wait until I try to figure out the types of S&W revolver types. "5 screw vs. 3 screw," etc. And why you want one over another. It's worse than Stanley wood planes. "What you got there is a type 13a Stanley #7 with a corrugated bottom. There are 3 patent dates and a Sweethart Iron. Depression era. A very good model... All the bells and whistles, and quality had yet to taper off at the factory..."
I haven't dove into the gun minutiae like I did with antique woodworking tools.
photo by Luigi Zansi