Benelli M4 -- Trigger, Disconnector and Hammer Disassembly

[StrangerDanger]

Hi all,

There have been some questions about how difficult it is to disassemble the trigger group of the Benelli M4 in order to install a US made hammer, disconnector and trigger. The difficulty level of this job depends on what tools you have on hand. With the wrong equipment, plan on swearing a lot. This disassembly requires that you manipulate a lot of small pins and springs. Do yourself a favor and get yourself a proper set of roll punches, roll pin holders, snap ring pliers, disassembly block and dental picks. Brownells has an awesome selection that will last you a lifetime.

 

First off, ensure that your Benelli M4 is unloaded. Remove all ammunition from the weapon and remove it from your work area.

 

Now, remove the bolt handle, and use it to push out the trigger group's Axle Bushing. Once it is started, you can pull it the rest of the way from the opposite side of the receiver. Press the bolt release and pull the trigger group downward and away from the stock. The entire assembly will pull out.

[StrangerDanger]

Now, take your snap ring pliers and remove the Trigger Guard Pin Spring from the Trigger Group.

 

[StrangerDanger]

 

Now, using a punch, push the Trigger Pin Bushing approximately half way out of the trigger group assembly. You do not want to push this pin completely out, since it retains the Shell Release Lever also. You want to push it out enough for the Hammer to detatch. Be careful of the Hammer Spring Cap. It is under spring tension and will launch across the room when the Shell Release Lever slips off of the top of the cap. Control the cap with your thumb as you relieve spring tension. Note the red line on the following photograph.

 

[StrangerDanger]

Once the Hammer is removed, you may now pull out the Hammer Spring cap and the Hammer Spring.

 

At this point, you can install your new hammer, or push the Trigger Pin Bushing back into place if you plan to further disassemble the Trigger Group.

[StrangerDanger]

Using a pick, disengage the Shell Release Lever Spring from the notch on the Shell Release Lever. This will relieve spring tension and make disassembly much easier.

 

Using a punch, tap out the Trigger Pin. Using a block such as the one in the photo below allows for the pin to fall out freely.

[StrangerDanger]

Once the pin is free, remove the Shell Release Lever Spring.

Edited September 11, 2012 by StrangerDanger

[StrangerDanger]

Now you can pull the trigger and disconnector assembly out of the Trigger Assembly.

 

Here is the trigger assembly without the hammer, trigger or disconnector.

[StrangerDanger]

 

Now, to further disassemble the trigger and disconnector. The Trigger Spring simply pulls out of the Trigger.

[StrangerDanger]

Using a punch, tap out the small Disconnector Pin. This will allow you to remove the Disconnector, the Disconnector Plunger and the Disconnector Spring. The Disconnector Plunger is under spring tension, so keep your thumb on it while you pull out the punch. Remember, once you push a roll punch all the way through, the punch will act as a slave pin and hold the assembly together.

 

[StrangerDanger]

At this point, you have fully disassembled the Trigger Assembly as much as needed to install the new Hammer, Disconnector and Trigger.

 

At this point, it is time to reassemble.

 

Install the factory Disconnector Spring and factory Disconnector Plunger into the Trigger you plan to use. The spring slips over the end of the Disconnector Plunger and presses into a hole in the trigger as shown below.

 

[StrangerDanger]

Insert your Disconnector as shown in the photograph. Prepare yourself for some swearing.

 

Compress the Disconnector so that you can pass your roll pin punch through the retaining pin hole. This will act as a slave pin and hold the assembly together as you try to insert the Disconnector Pin.

 

You can attempt to use a roll pin holder like shown below to assist with installing the Disconnector Pin, however the pin is so small that it is difficult to use since it barely protrudes from the Roll Pin Holder.

 

[StrangerDanger]

 

At this point, you can thank baby Jebus for your good fortune that you didn't loose that tiny pin.

 

Now, use a larger roll pin punch to seat the Disconnector Pin flush with the trigger.

 

[StrangerDanger]

Re-install the Trigger Spring into the Trigger. The spring simply presses in.

 

Now you have a fully re-assembled Trigger and Disconnector.

[StrangerDanger]

Hold the Trigger Assembly sideways as you re-insert the Trigger. You want to do this so the Trigger Spring won't fall out. Note the notch at the rear of the Trigger, this will engage with a pin in the rear of the Trigger Assembly.

 

 

Compress the Trigger spring and align the Trigger Pin hole. Insert your punch through the hole to act as a slave pin.

 

[StrangerDanger]

With the slave pin in place, push the Trigger Pin in from the opposite side to displace the slave pin. Note that you do not want to push the Trigger Pin all the way into the assembly yet. You still need to re-install the Shell Release Spring. So push the Trigger Pin through the assembly to where the blue line shows in the photo below.

 

 

[StrangerDanger]

Shell Release Lever Spring

 

Insert the spring into the Trigger Assembly with the small leg towards the rear of the Trigger Assembly and the loop at the top. Using a dental pick through the Trigger Pin hole and seat it in position so that the Trigger Pin can push through the loop of the spring. Do not try to engage the spring on the Shell Release Lever yet.

 

[StrangerDanger]

Once the spring loop is in place, push the Trigger Pin the rest of the way into the Trigger Assembly.

 

Now, using a dental pick, carefully bent the front leg of the Shell Release Lever Spring up, and hook it on the tab of the Shell Release Lever.

 

[StrangerDanger]

Here the spring is engaged properly.

 

At this point, the trigger and disconnector is completely reassembled into the Trigger Assembly.

 

Now, we'll move back to installing the hammer. Using a punch, press the Trigger Pin Bushing back out until the red line in the photograph below.

[StrangerDanger]

At this point, I'd recommend applying some grease to the hole in the hammer and along the sides around the hole.

 

 

Assemble the Hammer Spring Cap and Hammer Spring.

 

[StrangerDanger]

Insert the Hammer Spring Cap and Hammer Spring into the Trigger Assembly.

 

 

Compress the Hammer Spring cap and hook the tab of the Shell Release Lever over the top of the Hammer Spring Cap. You'll need to apply pressure to the Shell Release Lever so the spring tension of the Hammer Spring won't launch the spring and cap across the room.

 

[StrangerDanger]

Install your hammer with the hooks facing towards the rear of the Trigger Assembly. Now you need to align the hole in the Hammer with the Trigger Pin Bushing. The easiest way is to observe the hole from the opposite side to align the two holes. As alignment is met, press the Trigger Bushing Pin into the assembly. I press it in by pressing it against the work bench while I look from the opposite side.

 

 

Here, the Trigger Pin Bushing has beeen pushed most of the way through the Trigger Assembly.

 

[StrangerDanger]

Tap the Trigger Pin Bushing in with a punch and hammer all the way until the groove is visible.

 

 

Using your snap ring pliers, stage the Trigger Guard Pin Spring.

 

[StrangerDanger]

Install the Trigger Guard Pin Spring onto the Trigger Pin Axle Bushing. Note the grooves along the side of the bushing, the groove interface with the left and right side of the Trigger Guard Pin Spring if you consider the holes for the snap ring pliers as the top of the piece. I tap on the snap ring with a hammer and punch to make sure it is seated in the grooves properly.

 

I would recommend applying a small amount of grease to the hooks of the Trigger, Disconnector and Hammer.

 

Now reinstall the Trigger Assembly into the receiver. Install your bolt handle.

 

Ensuring that the weapon is unloaded, cycle the bolt to ensure the Hammer is cocked, engage the safety and attempt to pull the trigger relatively hard. Wiggle the trigger laterally to see if the hammer falls. Now disengage the safety and press the Trigger. The hammer should fall. Repeat this step several times to ensure that the components are working properly. Now test the disconnector. Pull the trigger and hold the trigger to the rear. After the hammer drops, cycle the bolt release manually while still holding the trigger to the rear. The Hammer should remain to the rear, if it falls forward, there is a problem. If the hammer is held to the rear, release the trigger. You should hear an audible click as the disconnector disengages and the hammer engages the Trigger Hook instead. The Hammer should not fall forward, if it does, there is a serious problem. Attempt this test several times to ensure proper function and safety.

 

 

 

These photographs will compare the factory and aftermarket Trigger, Disconnector and Hammers.

The Geissele/carriercomp Hammer is on the left. The Freedom Fighter Tactical Hammer is in the middle. The factory Benelli Hammer is on the right.

[StrangerDanger]

The Freedom Fighter Tactical trigger is on the top, and the factory Benelli Trigger is on the bottom.

 

The Freedom Fighter Tactical Disconnector is on the left, the factory Benelli Disconnector is on the right.

[StrangerDanger]

This is always an excellent reference guide.