M1 Carbine Part 3: Trigger Housing Group Disassembly

In M1 Carbine Part 1, we took a look at the external condition of the new old CMP M1 Carbine.

In M1 Carbine Part 2, we disassembled the M1 Carbine into its major groups.

In this edition of M1 Carbine adventures, we’re going to disassemble the Trigger Housing Group.

The first step is to remove the hammer spring and hammer spring guide.

First, decock the hammer. I would assume that my readers will know how to do this but there is one oddity in the M1 Carbine: The spring tension on the hammer pushes the sear into place. If you remove the tension of the hammer against the sear, the trigger will not engage the sear and the hammer won’t release; so, just place your thumb lightly on the hammer to catch it once it releases, but don’t put any rearward pressure on it; otherwise, it won’t release when you pull the trigger.

With the hammer decocked, place a punch into the hole in the hammer spring guide. Pull the guide back until it disengages from the detent in the hammer.

Turn the punch and guide until you can move the guide off to the right side of the hammer.

Once clear of the hammer, release the tension on the spring and remove the spring and guide.

The next step is to remove the hammer.

Simply remove the hammer pin and the hammer will lift right out.

On mine, the hammer pin was loose in the assembly so it didn’t require a punch, It just pulled right out.

Next is the trigger spring. It is in housing above and to the rear of the trigger. You can see the back of the coils through a hole in the rear of the housing.

I used a dental pick to pry the bottom of the spring from its detent in the trigger.

It took a little jiggling and twisting but it popped out with out too much trouble. You could probably remove it through the rear hole also, but it seems like it would be much more difficult to get out that way.

Next to come out is the trigger pin which releases the trigger, sear and sear spring. The sear spring is in a well in the face of the trigger and presses against a detent in the bottom rear of the sear. You can’t see it until the sear is removed but be aware that it is there because it is fairly small and would be easy to lose.

Again, removing the pin did not require a punch, it was not a tight fit and pulled right out.

Put rearward pressure on the sear to prevent the spring from pushing it out too quickly, pull the pin and then gently release the spring tension. Lift out the sear, then lift out the trigger, being careful not to lose track of the spring.

The magazine catch involves two springs. One is the safety spring that goes fore and aft in the assembly and has a plunger at either end. The front plunger rests in a groove in the magazine catch and holds the catch in place. The rear plunger holds the safety switch in place and provides positive locking for the “safe” and “fire” positions of the switch.

Because the safety spring holds both the magazine catch and safety in place, the safety switch cannot be removed until after the magazine catch is removed.

There is a hole in the bottom of the housing through which you can see the front plunger of the safety spring.

The magazine catch spring runs laterally into a well in the housing and places outward pressure on the magazine catch button. This is what holds the magazine catch closed after a magazine is inserted.

Press slightly in on the magazine catch button to release any tension of the catch on the safety spring. Use a scribe or jewelers screwdriver to pry the safety spring plunger to the rear which will release the magazine catch. Gently release the spring tension of the magazine catch spring.

Once the magazine catch has been released and the spring has pushed it partially out of the housing, the scribe or screwdriver you are using to pry the safety spring plunger back can be removed. Place a finger across the front of the catch to prevent the safety spring from shooting out and pull the magazine catch to the side and off; then pull the magazine catch spring out of its well in the housing.

After the magazine catch is removed, tip the assembly forward and catch the safety spring as it falls out of its well in the housing.

Then the safety switch can be pulled from the housing.

And there you have it; one M1 Carbine Trigger Housing Group (some assembly required).

In the next episode, we’ll disassemble the Bolt…the hard way.


5 thoughts on “M1 Carbine Part 3: Trigger Housing Group Disassembly

  1. Sorry for the delay in posting and responding to this comment. I have comment moderation turned on for older posts to prevent the Chinese Viagra spam and It's been a few days since I checked the moderation queue.

    A trigger housing marked Q-NL is either a type II or type III manufactured by Quality Hardware…most Likely a type III…the easiest way to tell is to look down on the rear of the housing from the top. If the rear lug that secures the housing to the receiver is square, it's a type III, if the lug has beveled rear corners, it's a type II.

    Hope that helped.

  2. Pingback: M1 Carbine Part 5: Stock/Receiver Disassembly | Captain of a Crew of One

  3. Pingback: M1 Carbine Part 7: Trigger Housing reassembly | Captain of a Crew of One

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