Jump to content
Search In
  • More options...
Find results that contain...
Find results in...
Benelli Forums
StrangerDanger

Benelli M4 -- Shell Stop Removal & Install

Recommended Posts

Hi all,

I had a request to do a detailed pictorial on the disassembly of the Shell Stop. Removal of the Shell Stop is the same for the factory and GG&G model. In fact, the GG&G model is simply a modified factory Shell Stop.

 

Start out by unloading the weapon and setting the ammuntion away from the work area. Field strip the M4, remove the barrel assembly, bolt carrier and trigger group. The stock may be left on.

 

001.jpg

 

This is a view of the inside of the receiver. It shows the placement of the Shell Stop Spring. The spring is a loose fit, so you should note its position before disassembly.

002.jpg

Share this post


Link to post
Share on other sites

003.jpg

In this photograph, the Shell Stop Pin is annotated over the photograph. This is the only pin that retains the Shell Stop and Shell Stop Spring in place.

 

005.jpg

In this photograph, the red line indicates the Shell Stop Pin channel. The Shell Stop Pin passes through the guide rails that the bolt carrier rides along.

Share this post


Link to post
Share on other sites

011.jpg

This is the top of the Shell Stop Pin channel.

 

012.jpg

The blue lines indicate the channel that the bolt carrier reciprocates in. The red line shows the placement of the Shell Stop Pin.

Share this post


Link to post
Share on other sites

013.jpg

I find it best to use a punch to drive the Shell Stop Pin out from the bottom upward. I don't usually remove the pin completely from the receiver. I drift it upwards enough to remove the Shell Stop.

 

014.jpg

Once the pin has been drifted into the channel that the bolt carrier reciprocates in, the punch will act as a slave pin holding the Shell Stop into the receiver.

Share this post


Link to post
Share on other sites

015.jpg

This angle shows the Shell Stop Pin protruding through the rail and part of the way out of the ejection port. As the punch is removed from the receiver, the Shell Stop and Shell Stop Spring will fall out of the receiver.

 

016.jpg

Share this post


Link to post
Share on other sites

017.jpg

The Shell Stop Spring simply sits in the recessed groove at the rear of the Shell Stop.

 

018.jpg

This is the back side of the Shell Stop. The edge at the left is what retains the shells within the magazine tube. The right side indexes with the Shell Drop Lever in the trigger group.

Share this post


Link to post
Share on other sites

020.jpg

This photo shows the base of the Shell Stop Pin drifted up high enough for the Shell Release to be removed from the receiver. The pin is visible protruding through the ejection port.

 

 

021.jpg

Share this post


Link to post
Share on other sites

022.jpg

This image shows the Shell Stop and how it indexes with the Shell Release Lever.

 

Now it is time to reinstall the Shell Stop. Insert the Shell Stop Spring into the Shell Stop.

023.jpg

Share this post


Link to post
Share on other sites

024.jpg

 

Place the Shell Stop and Spring back into the receiver. Try to keep the spring properly aligned at the rear of the Shell Stop.

 

 

025.jpg

 

Compress the Shell Stop and insert a slave pin through the Shell Stop Pin channel until it makes contact with the Shell Stop Pin. It'll take some effort to align the Shell Stop. I typically look down the hole of the Shell Stop Pin channel and visually align the holes. Then insert the slave pin to keep the assembly together.

Share this post


Link to post
Share on other sites

027.jpg

 

This image shows the slave pin in place. I applied blue painters tape to the top of the ejection port to protect the finish.

 

028.jpg

 

Here, I am using a roll pin holder that slips over the end of the Shell Stop Pin. I drove the pin back down and displaced the slave pin.

Share this post


Link to post
Share on other sites

029.jpg

 

This image has the bolt carrier channel superimposed over the receiver to show you the exact depth needed to seat the Shell Stop Pin. While driving the pin in, I squeeze the Shell Stop against the Receiver. This aids in aligning the holes for the pin to transit. When you're tapping the pin in, you have to listen and feel for the pin actually drifting. If it sounds like you're delivering a dead blow to the pin and it isn't moving, stop and back the pin out from the opposite way if needed. You don't need a lot of force to move this pin. I use a 4 ounce hammer with maybe a 4 inch swing.

 

030.jpg

 

At this point, the roll pin holder has bottomed out against the ejection port. Now I'll switch to a roll pin starter punch.

Share this post


Link to post
Share on other sites

031.jpg

 

The dimple on the end of the Roll Pin Starter Punch indexes with the hole in the Roll Pin. These keep the punch from slipping off the roll pin.

 

032.jpg

 

This is the best way to hold the tool and still apply pressure to the bottom of the Shell Stop. The blue line shows the current position of the Shell Stop Pin. It's still obstructing the channel for the Bolt Carrier at this point.

Share this post


Link to post
Share on other sites

033.jpg

 

In this shot, it shows that the roll pin has not been seated far enough down the channel. A portion of the pin is protruding into the channel for the Bolt Carrier.

 

036.jpg

 

In this image, the roll pin has been seated successfully far enough into the channel. Be sure that you do not seat it too far though. The roll pin should not protrude from the bottom of the receiver at all either.

Share this post


Link to post
Share on other sites

037.jpg

 

Here is why taping up the receiver is a good ideal.

 

038.jpg

 

If you're installing the GG&G unit, note how the pad indexes with the keyed Shell Stop button. I noticed that the button will fit differently if you rotate it 180 degrees. In one position, the button rides higher up the receiver. Neither is wrong, it is just personal preference.

Share this post


Link to post
Share on other sites

Wow SD!!! Thanks for all your good efforts on this one... I was actually planning to install my GG&G pad this weekend so your timing with this thread is excellent. I think I'll pick up the roll pin holder and starter punch. I just have a regular punch set and I always get a little nervous dealing with roll pins. Nothing like the right tools for the job to make sure all goes well.

 

 

Thanks and Take Care,

 

 

Hookster :)

Share this post


Link to post
Share on other sites

Another user sent me a tip about putting a self adhesive velcro sticker on the back side of the pad if you want to prevent it from marring your receiver. My receiver is already pretty well beat up, so it didn't matter to me if it scratch the finish.

 

In a month or two, I'm going to do a pictorial on how to tear down the receiver extension when I get my extra extension back from WMD Guns.

Share this post


Link to post
Share on other sites

Brownells Roll Pin Punch Set & Bench Block

http://www.brownells.com/.aspx/pid=27552/Product/ROLL-PIN-PUNCH-SET

 

Brownells Alignment Pins

http://www.brownells.com/.aspx/pid=364/Product/ALIGNMENT-PUSH-PUNCHES

I only have the steel set of these. I really didn't have much purpose for the brass ones. However, sometimes it would be nice to have two of the same size alignment pins.

Share this post


Link to post
Share on other sites

Brownells Dental Picks

http://www.brownells.com/.aspx/pid=9809/sku=700-410-000/Product/Dental-Explorers-Set

http://www.brownells.com/.aspx/pid=25538/Product/STAINLESS-STEEL-DENTAL-SCALERS

Buy these. I used to bend paperclips to try to capture spring legs. Do yourself a favor and buy these and save yourself the headaches involved. Note there are different styles available. I tend to use the scalers the most due to the tip strength.

Share this post


Link to post
Share on other sites

I know this thread is ancient but anyone know the actual size punch that is needed for this?

Share this post


Link to post
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.

Guest
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...