On a Final Note
...before I back outta this one.
Study the parts in the 1911's trigger group, and their relationships for a
minute and consider them carefully.
"Smithed" hammers and sears generally fall somewhere in the neighborhood of .018 to .020 inch long hammer hooks. That's just a tick
over a 64th of an inch. Sear primary angles run about .015 inch wide...
which is just a fractional amount UNDER a 64th. That's not much, considering how violent and slam-bang the cycle of the .45 auto is.
The hammer hooks are generally cut as close to dead square as can be managed, and the sear's primary angle...the engagement surface MUST
agree with the hammer hooks AS INSTALLED IN THE GUN. If those
angles don't agree, you may have a time-bomb on your hands. It only
takes a half-degree mis-match in either one, and that "Drop-In" trigger
group that feels Oh-So-Sweet today will be a completely different animal
5 or 6 thousand rounds down the road. Sometimes the warning signs that
something is wrong are so subtle that they're missed...or even ignored.
Even with a precisely fitted trigger group, things wear and things change with use. Springs fatigue. Contact surfaces polish themselves and the
angles change.
The original specs called for a light captive angle on the hammer hooks, and a matching primary angle on the sear. The hammer hooks themselves were set at about .030 long...Nearly twice as much as the hooks on the hammer of a "tuned" trigger group, so that when the hammer bounced off the sear, it had enough length that the sear would catch it, and the captive angle would force the sear back to the bottom of the hooks.
All this made for a heavier trigger pull...some heavier than others, depending on how sharp the captive angle was...but it made for a pistol
that was much less apt to go full auto, even with thousands of rounds worth of wear on the parts.
Match-tuned triggers have been around almost as long as the gun itself...
but those pistols were meticulously maintained, and the trigger groups were re-done or replaced often.
'Nuff said. Ya'll be careful with the project.
Tuner