Short trigger and arched MSH installation on series 80 Colt


November 4, 2006, 09:01 PM
I am considering getting a series 80 Colt, but I prefer a short trigger and arched mainspring housing.

Will an original series 70 short trigger fit in a new series 80 without any modification?

Would replacing the mainspring housing require any special fitting?

I'm no gunsmith. Are these modifications something best left to a good gunsmith, or something I could easily do myself?


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November 4, 2006, 09:13 PM
It shouldn't be a problem. I swapped out both on my NRM 80. I prefer the old school arched mainsprings. I also removed the series 80 safety and replaced it with the piece from Brownells to fill in the space. Here is more info taken from 1911 Forums:

In light of new members comin' in who want to know what the differences are between the Series 80 Colts and the original design 1911s...

There are 4 additional parts...two in the frame and two in the slide.

Frame: Trigger bar lever and plunger lever.
Slide: Firing pin plunger and the spring that drives it.

There are also differences in some Series 80 parts. The parts that are modified are:

Grip safety...Firing pin...Firing pin stop...Extractor. All other parts are the same. The named Series 80 specific parts will work in Series 70 and pre- Series 70 pistols without modification, but not vice-versa unless the frame levers and the plunger and spring are removed from the Series 80 pistol.

The half-cock notch on the Series 80 hammer is also different, but all hammers
will physically interchange between the two designs. You can use a pre-80 hammer in a Series 80 pistol with the system intact. Likewise, a series 80 hammer will work in a pre-Series 80 pistol.

Swapping triggers between the two designs will physically work, but if the
bow is a little too short, the trigger bar lever may not move the plunger lever
upward enough to release the firing pin completely. There is a simple check
for that possibility in the event of a trigger change, and should be done
whenever a trigger is swapped.

Triggers with overtravel screws are also a potential trouble spot in a Series 80 pistol. If the trigger travel is limited to the minimum by the screw, the same
caution applies as above.

The difference in trigger pull between Series 80 and pre-Series 80 pistols is
negligible, assuming the same geometry and surface prep/finish on the related trigger group parts.

The Series 80 system does NOT make the pistol more safe to carry in Condition One, contrary to many widely-held mistaken beliefs. It's also no LESS safe. Both systems require that the trigger be pulled before the gun will fire, assuming that the thumb safety is OFF and the grip safety is depressed.
The Series 80 passive firing pin block only renders the gun more drop-safe.
All else is equal. Bottom line: It's a GUN. It's NOT safe.

Zach S
November 4, 2006, 09:15 PM
Both are pretty much drop in parts.

Adjusting the take-up and overtravel isnt hard, and thats about all there is when installing a trigger. With some triggers you cant adjust take-up or overtravel without modifying the trigger. The Colt trigger I put in my SA milspec didnt have provisions for either, neither did the SA trigger it replaced.

If you can detail strip it and get it back together, you shouldnt have any problems. If you cant deail strip it, have a smith do it.

November 4, 2006, 09:23 PM
Yes, they will swap out, and yes, you can do it if you can detail strip the pistol.

If you don't know how to detail strip a 1911, go here (

Go here ( for trigger installation details.

November 4, 2006, 09:27 PM
The other choice is a new production series 70 which already has short trigger and arched MSH, but I don't like the look of the stainless hammer. Can you get an all blued spur hammer for these? I can't seem to find one available.

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