Jump to content

Benelli M4 -- Trigger, Disconnector and Hammer Disassembly


Recommended Posts

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.


Link to comment
Share on other sites



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.



Link to comment
Share on other sites


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.



Link to comment
Share on other sites


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.



Link to comment
Share on other sites


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.



Link to comment
Share on other sites

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.



Link to comment
Share on other sites

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.





Link to comment
Share on other sites


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.



Link to comment
Share on other sites

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.



Link to comment
Share on other sites

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.



Link to comment
Share on other sites


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.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...