How to install a Magazine Extension Tube on a Remington 870

After trying to find a good how-to on installing a magazine extension tube on my Remington 870 (and coming up with a bunch of articles that contradicted themselves), I decided to make my own. This tutorial will hopefully clear up some of the myths out there that you may encounter when trying to do this yourself.

Tools:
17mm socket (this was tricky since each socket's walls have different thicknesses depending on the brand. I used a Snap-On 1/2inch socket)

Ratchet, size:Depends on what socket you use. You'll see the reason shortly.
Rubber hammer
Flat Head Screw Driver
A buddy of yours to hold the gun.



Instructions:

1) First take the end locking nut off located at the end of the mag tube. To do this, just unscrew it.


2) Using the flat head screw driver, push down and turn the spring retainer until it comes out. (Warning: the spring retainer is under pressure and may shoot out. Take caution near face).


3) Remove both the spring and the spring retainer.


4) Take the socket and place it over the mag tube. (Make sure that the socket is a good fit. Not too big or it will engulf the tube. Not too small or it will push out the piece of metal that stops the shell from going any further).


5) Have your friend hold the gun on a sturdy surface and hit the socket into the mag tube. Make sure the socket is facing the way that you will be able put your ratchet on and unscrew it out.


6) Once you have hit the socket in, put the ratchet on, and unscrew it out. Repeat steps 5 and 6 until a shell can smoothly go through it.


7) Once this is complete, you can now install the Magazine Extension Tube and the spring that comes with it. Note: you may need to cut the spring depending on what size mag extension you bought because most companies will have one, universal spring for all kits. Don't fret; this is not a big deal. All you have to do is use a pair of wire cutters to cut small sections out of the spring and test it to see if it will hold the right amount.



I hope you guys have found this helpful and if there is any part that needs clarifying please let me know and I will to my best to try and help you out.

Thanks. That helped a lot

Glad to help.

Good job on the tutorial DT !!

Was the 17mm socket tight to start in the tube before it got to the dimples? All of my 17mm seem to tight to start in to the tube.

Don't bother to reply. I found a 17mm that fits. Oil hammer twist hammer repeat. Got it!!!

I followed this method but can't figure out how to get the barrel to smoothly slide on and of the magazine afterwards. Anyone come up with a solution?

Just used this 17mm socket method last night it worked great.[ The socket must slide into the mag tube easily before it contacts the dimples or it is to big.] It sounds like you have hammered the end of your mag tube to a over sized state. Not good! Does the mag cap still screw on?

I just had to dremel the magazine tube ever so slightly and now it works great.

glad to hear it worked out.

I tried this the other night with my 870 and none of my sockets (Craftsman) are sized correctly, they are either a hair to small or just a hair to big. I may have to grab my calipers and head to the hardware/auto parts store to find one that will work.

I know what you mean, it look me longer to find the right socket that fit than to actually do it.

Found the perfect size over the weekend. I did have to do a little tapping with a hammer on the outside of the dimples as they pushed out a little but it worked like a charm.

Glad everything worked out.

Does anybody know of US web pages that sells Original Remington +2 magazine extension, and ships to Norway?
Everybody I found on eBay does not ship to Norway
It's not illegal here, but in Norway it cost over $130 + shipping $20..

Welcome to the Remington Owners Forum Fjellvang !!

I'll see if I can find one...but you're correct that most US based companies don't like to ship outside the country.

I have managed to buy 2 tactical stocks from a US manufacture.
I just wrote them a e-mail and asked if they could ship to Norway, and then we took the order over the mail
I have attempted that with several sellers on eBay, but none of them want to ship outside the US..

I am glad you were able to get them shipped to you. Let us know how you like them.

Thank you for this! I couldn't find the perfect socket, but took the closest fitting one and took a bench grinder to it. Worked great!

Glad it helped

No worries

What's the best brand on the +2 magazine extensions? Reliability is my priority.

Degadep wrote:What's the best brand on the +2 magazine extensions? Reliability is my priority.

Nordic is good but I'm not sure if they make one for the 870.

I have an older ATI on my 870. It's the older style plastic version. It works OK but it's a little bulkier than the metal versions.

You can also look at Choate, ProMag, TacStar, Carlsons.

Remington makes one as well but it replaces the entire magazine tube.

Which is the best? .....I could not tell you as I have not used enough of them to make a fair comparison.

Going deep here to resurrect a very old thread.......

I used a rotary tool to smooth the tube dimples. Super easy, took just a few minutes. Lightly oiled the exposed metal and re-assembled. Everything fit and worked fine, no hang ups.

My 4+1 Express is now a 6+1.

The extension I bought was advertised as an OEM +2. Not totally sure it's OEM as I don't see 1-piece mag tubes on the Remington Canada webpage. All appear to 2 or 3 piece units. However, I know there have been countless models and iterations of the 870 for civilian, military and police applications and some marketed new with another manufacturers accessories...so again, I'm not sure.

Maybe someone here on the board knows?

I think I'm just about done with upgrades to my 870 now...20" barrel, mag tube extension and custom paint job. Only thing I might like to do now is add a light. But I'm not sure. Lights look so bulky on the front end........