How to Install a MAGPUL SGA® Stock and MOE® M-LOK® Forend

For quite some time I have had a little Remington 870 sitting in the gun safe. I picked it up super cheap, stuck it in there, and forgot about it.

A few weeks ago I was in my safe and happened to see it stuck in the back. I have to admit, its plain, boring look has probably been the main reason it remains untouched.

Remington 870

It was time for a change. I decided to see what I could do to make it a little more appealing or interesting in the hopes it would cause me to spend more time shooting it.

So, like a lot of folks, I decided to start with installing a new stock and forend, both from Magpul. They are “cheap”, easy to install, and add a fresh look to an old gun.

So, since Magpul has limited offerings in this area it made the decision process pretty easy. I hopped online and found some decent deals on a Magpul SGA® Stock and Magpul MOE® M-LOK® Forend, both in black.

I’m not sure where this project will end up going, but for now I’m sticking with the installation of these two products.

Since installing the SGA Stock is so simple, let’s start with it first.

How to Install a MAGPUL SGA® Stock

The main thing we always focus on is safety! Make sure your weapon is unloaded. Check both the chamber and magazine tube by visually looking at them and by feeling around with your fingers. Once you are 100% certain the weapon is safe you can proceed.

In order to remove the factory stock, you will start by focusing your attention on the recoil pad. What you will notice is there are two small holes at the top and bottom of the recoil pad.

Use a Phillips head screwdriver to remove the two screws hidden within the holes. Once you insert the screwdriver all the way into the hole, twist while rotating the screwdriver counter-clockwise and you will feel it grab.

After the two screws are removed, the recoil pad can be pulled off of the stock.

Now that the recoil pad is removed, you will notice a screw recessed in the center of the hollow stock.

Use a flathead screwdriver to remove this screw. It is pretty long and will take a little bit of work to completely remove it.

When the screw is completely removed the stock you will be able to detach the stock from the receiver. You will not be reusing the stock and screw or recoil pad and screws.

You are now ready to install the new SGA Stock.

The first thing you will do is locate the receiver plate and line it up evenly on the receiver.

The stock will now line up on the receiver. Make sure the receiver plate is evenly lined up between the two. Once everything is even, install the included bolt with a 3/16″ hex key and tighten (DO NOT OVER TIGHTEN).

Once the bolt is snug, give everything a good look to make sure it’s all properly installed.

Now it’s time to install the thumb strip over the recently installed receiver bolt. Simply slide the end without the texture into the bottom part of the groove and work it into place from the bottom up. You should get a nice, flush fit.

That is it! Pretty simple and straightforward. Not to mention, how different it looks.

Now that the stock is complete, let’s move on to the forend.

How to Install a MAGPUL MOE® M-LOK® Forend

In order to replace the forend, we need to start by removing the magazine cap, barrel, castle nut, and factory forend.

Let’s start with the magazine cap, which is at the end of the magazine tube. Rotate it counter-clockwise to remove.

After you remove the magazine cap, you should be able to remove the barrel of the shotgun with a little pulling and coercion.

The factory forend is held on by a castle nut, which needs to be removed. use the included castle nut tool to remove the castle nut.

Now that the castle nut is removed, you should be able to remove the factory forend. Slide the new forend onto the magazine tube until it is seated all the way into position.

Slide the castle nut back into position, and again use the included castle nut tool to tighten down the castle nut. DO NOT OVER TIGHTEN!

Reinstall the barrel and magazine cap by reversing the directions above. Again, perform a solid visual inspection to make sure everything is installed properly.

Again, the visual difference is pretty significant.


I highly recommend you head to the range once your installation is complete. It’s always a good idea to test your weapon after any modifications just to make sure it is fully functional. You never want to put your life in the hands of an unproven weapon.

I’m not sure what’s next on my list, but I’m thinking about a magazine tube extension, possible weapon mounted light, and who knows what else.

Stay tuned!

Cody Martin

With over 18 years of federal law enforcement, training, and physical security experience, Cody focuses his time nowadays on both consulting and training. He regularly advises individuals, groups, multinational corporations, schools, houses of worship, and NGOs on security threats while conducting customized training as needed.

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