Jammer, you said McCormick hammers, I didn't see that before. They are supposed to be drop in parts and from what I've heard they work pretty well that way on some guns at least, I don't use them so I can't give first hand info. I believe Chip uses a little different geometry on his hammers and sears, I talked to him when he first came out with them and IIRC that's what he told me. If you stuck them in a jig and started stoning I can see what happened. I would give McCormick a call and ask them.
I do trigger jobs from under 1lb on some specialty competition guns to carry type trigger jobs. I don't believe in drop in trigger jobs although lots of people have told me they dropped in some parts and have a great trigger. I spend a lot of time on trigger jobs, nothing has ever dropped in for me. There is a steep learning curve to learning how to properly set up a 1911 trigger, I've been doing them for 30 years and am still learning. I have developed a method that works for me, other gunsmiths go at it a different way and have success, there is more than one way to skin a cat. This is why you get different information from different smiths and it all could be correct but it may not all work inconjunction with each other. Some guys seem to be emotionaly attached to their methods and will attack anyone who does it different. I can understand that in a way, you pay a pretty good price to learn how to do it right but I try to stay open to any good ideas. It's hard from my perspective to encourage folks to do their own, if they really are dedicated and will learn enough to do it right I'm all for it. Most seem to just want to save the few bucks us gunsmiths make on a trigger job, that's the ones that worry me. We have a saying around my shop " to the amateur everything seems easy ".
Fuff, that last photo does look pretty nice but I see some editing in there, one of my hobbies is photoshop. So how much touching up did ya do?
I still don't think that square corner is neccessary but like I said if it works for you good on ya.
Some of the really good hammers are made of S7, real tough stuff. You better have a rigid mill and some really sharp cutters if your going after the hammer hooks on one of these babies. I got digital and it's nice but I can still mess up if I try hard enough!!
The C&S hammers I get in are pretty nice right out of the package, not seen one yet that had bad hooks, not saying I don't do some prep work on them.