Since I began this series, I’ve received a lot of requests for a video on take-down
and reassembly of a Remington 870. This isn’t something I had initially planned to cover;
the 870 is a pretty simple design, and basic instructions are readily available.
However, the brief written instructions in the owner’s manual leave much to be desired.
And while there are a lot of how-to videos and other online guides already out there,
even the better ones I’ve come across only show the process for one type of 870.
So, I felt I could contribute by creating a more exhaustive disassembly guide that would
explain and demonstrate each step in greater detail, cover all standard 870 models and
configurations, give accurate part names, and help new owners avoid the common mistakes
and hang-ups that most people figure out the hard way.
Of course, all that detail and inclusiveness doesn’t exactly make for a brief video,
but don’t let the runtime scare you off. I’ve added DVD-style forward and back buttons
down here in the corners. If you have annotations turned on, you can use the back button to
replay previous steps; and the forward button to skip past steps that you don’t need help
with, or that don’t apply to you. In addition, there’s a video outline in
the description with clickable timecodes for each step, so you can see at a glance how
this video is organized, and jump directly to a particular step at any point.
Alright, let’s get started. As always, the first step is a safety check.
Make sure the gun is on safe, and the chamber and magazine are empty.
When I'm doing a complete take-down, the trigger plate assembly usually comes out first. It
can be removed at pretty much any point in the disassembly process, but I’ve found
that having the trigger plate and shell carrier out of the way makes other steps a little
easier. The trigger plate is held in by two trigger
plate pins. Pushing these out is best done with a thin screwdriver or punch, but anything
sufficiently stiff and narrow will work in a pinch. I’ve even used the stem of a Tootsie
Pop before. But if you want a dedicated pin-pusher tool, a cheap scratch awl like this will work
just as well as a more-expensive “official gunsmith tool”.
You can remove your pins in either direction, but the way these guns come from the factory,
it’s easiest to push out the front pin from right-to-left, and the rear pin from left-to-right.
If you like, you can switch the front detent spring over to allow both pins to be easily
removed and reinstalled in the same direction. See this video for details.
Before removing the pins, close the action to take any downward force off the trigger
plate assembly. Now, holding the receiver up off your work
surface, place your tool in the center of the pin and push it straight through and out.
Put it somewhere where it won’t roll away and get lost, then turn the gun over and repeat
the process with the other pin. If you’re having difficulty simply pushing
a pin through, use one hand and arm to support the gun and hold the tool in place, then gently
but firmly tap the pin through with your other hand. If you don’t think you’re that coordinated,
you can also place an object under the gun to support it, or sit down and lay the gun
across your knees. You shouldn’t need to hammer on the pins
to get them out. These aren’t tight-fitting friction parts, each pin is held in place
by a single detent spring that engages one of these notches. Moderate force or a couple
light taps should be sufficient to disengage the pins from their detents, and they’ll
come the rest of the way out fairly easily. Once both pins are out, grasp the back of
the trigger guard, just below the safety button, and with a little pull and a slight forward
rotation, the trigger plate assembly should slip right out.
Some aftermarket furniture will enclose the rear of the trigger plate, and must be loosened
or removed to take out or replace the trigger plate assembly. If you’re not sure how to
do this with your specific stock or grip, refer to the product’s instructions or contact
the manufacturer. A number of popular aftermarket accessories
replace the trigger plate pins with their own mounting fasteners, which should be self-explanatory.
When the trigger plate assembly is out of the gun, keep the safety engaged at all times
so that you don’t accidentally pull the trigger and allow the hammer to snap forward.
It isn’t the end of the world if this happens, but it’s not great for the trigger assembly
parts, and it could be painful for you. If you do want to release the hammer for cleaning
or inspection, hold it down while you pull the trigger, then let it up gently; and return
it to the cocked position before putting it back in the receiver.
The next thing to come off is the magazine cap or magazine extension. This is what holds
the barrel in place. If you have a magazine cap, simply screw it
off counterclockwise. You should be able to do this by hand, but if it’s too tight or
you can’t get a good enough grip, use a pair of channel-lock pliers to break it loose.
To keep from chewing up the part, wrap it with a rag or a scrap piece of leather, and
make sure you have the pliers oriented correctly so that they don’t slip.
Now, even when empty, the magazine spring will be under compression inside the tube,
and it can launch a cap with impressive force. 870s without magazine extensions usually come
from the factory with a magazine spring retainer that holds the spring in the tube when the
cap is removed, but this is an optional part that not all owners opt to use. If there is
a spring retainer, leave it in the tube for now. If you want to take it out, it’ll be
easier to do so later on. If your gun doesn’t have a spring retainer,
or you’re not sure if it has one or not, hang onto your cap as you remove it. If your
gun doesn’t have a spring retainer, go ahead and pull out the magazine spring so it won’t
be in the way. Shotguns used for hunting may also have a
magazine plug that limits the gun to a legally-mandated capacity. These vary, but usually take the
form of a slender rod that sits inside the spring.
If you have a magazine extension, any reinforcing brackets or other tube-mount accessories need
to be removed before the extension can come off.
To take off a factory magazine extension bracket, use a flathead screwdriver to remove this
screw, then slide it off the front of the gun. If the bracket doesn’t slide freely
once the screw is out, pull it open slightly so it won’t scrape up the gun’s finish
as it’s removed. Aftermarket clamp-on accessories will vary.
I won’t try to cover every possibility here, but they’re not usually too tough to figure
out. Again, refer to instructions or contact the manufacturer if needed.
Once everything’s off the extension, unscrew and remove it just like a magazine cap. Again,
the spring will be under compression even if the magazine is unloaded, so hang on to
it if you don’t want it to go flying across the room. And with longer extensions, control
the spring as it’s released so it doesn’t tie itself in knots.
With the magazine cap or extension removed, place the fore-end in the middle of its travel
so that the bolt will unlock, but the back of the fore-end won’t get in the way; then
slide the barrel straight out of the receiver and off the magazine tube.
With some specialty slug hunting 870s, the barrel can be pinned directly to the receiver
with a single screw. If present, this screw must be removed before the barrel will come
off. Some 870 barrels come with removable, interchangeable
choke tubes, or other choke-mounted accessories like the breaching stand-offs on some tactical
models. You can easily figure out if you have a removable choke by looking at the muzzle.
Removable choke tubes simply screw out of the barrel. Flush-fit tubes and some extended
ones have notches in the end to accept a specialized choke wrench or key, but an appropriately-sized
flat object like a coin will work too. Many extended choke tubes can simply be removed
by hand. A choke tube may take a bit of torque to break
loose, but then, it should thread out easily if it’s in good condition. If a tube refuses
to move, the threads may be rusted, damaged, or otherwise frozen up. If you suspect this
to be the case, and you’re not sure how to deal with a locked-up choke tube, take
the barrel to a gunsmith or other experienced individual. Trying to force it out may just
make things worse. With the tube removed, the end of the barrel
is very thin and easy to damage, so be gentle with it, and NEVER fire the gun without a
choke tube installed. For more information on caring for choke tubes, see this video.
With the barrel off the gun, the fore-end assembly and the rest of the action come out
together, but the left shell latch has to be held down to let the action bar by.
When I do this, I hold the fore-end in one hand and the receiver in the other. Using
a thumb or finger, I’ll reach through the bottom of the receiver and depress the shell
latch. With the other hand, I’ll slide the fore-end assembly and bolt components forward
out of the receiver and off the end of the magazine tube.
If you’re depressing the left shell latch properly, these components should slide out
very easily, so if something hangs up, don’t force it.
Check the bottom front corner of the ejection port. The slide assembly can shift up out
of its notches in the action bar and catch right here if you’re not holding the gun
upright, or inadvertently pushing up on the slide assembly. Make sure the slide assembly
is sitting down in the action bar, and it should come out unhindered.
Once they’re out of the receiver, the breech bolt and slide assemblies can be lifted off
the action bars. Now, the only remaining step is to remove
the spring retainer if your gun has one - and you want to remove it. Normally you can leave
this where it is if you’re just changing barrels or cleaning the action, but if you
want to pull your magazine apart during a full take-down, it’s less of a hassle
with the barrel and fore-end assembly out of the way.
There are two types of spring retainers. The old-style retainers are sheet-metal parts;
while new-style spring retainers are plastic, and have teeth molded into the front end that
help to keep the magazine cap from backing off.
The older-style spring retainers are held in the magazine tube by friction alone, and
you’ll need an appropriate tool to pry one out. Any slender, stiff object that will provide
the proper leverage like a screwdriver, Allen wrench, or even a long nail will work. I just
use my trigger plate pin tool. When prying out a metal retainer, never work
your tool directly against the edge of the magazine tube. This can permanently damage
the tube or its threads. Instead, insert your tool into the hole in the center of the retainer,
and use the retainer itself as a fulcrum, moving the tool around to work it out of the
tube bit by bit. Also, remember that there’s a compressed
spring inside the tube, so be ready to catch the retainer as it comes out, and don’t
point it at your face. The newer-style plastic spring retainers are
much less of a headache to take out. These are held in the magazine tube by a pair of
partial-length slots that engage two dimples stamped in the end of the tube.
To remove one of these, insert a flathead screwdriver into this slot. Then, simply push
the retainer back into the tube and past the dimples, give it a quarter-turn to line up
the dimples with the full-length slots, and let the magazine spring push it past the dimples
and out of the tube. This can also be done without tools, just
a finger, but it’s easier to use a screwdriver if you have one handy.
If you want to remove the magazine follower, hold the receiver at a downward angle, and
it should slide out, though you may have to give it a little push to get it going. If
your magazine tube has the dimples in the end, you’ll need to line up the two slots
in the follower with the dimples to get it out of the end of the tube.
If the follower gets stuck for some reason, you can insert your magazine spring into the
tube from the receiver end and push it out. And that’s a basic disassembly of a Remington
870. At this point you can see just how simple these guns really are to work with.
I have some other videos planned showing how to take the gun apart further - I’ll leave
annotations here when I get around to them - but this is as far as you should have to
go for normal cleaning, maintenance, and configuration. Now for reassembly.
For the most part, the gun goes back together the same way it came apart; but there are
some differences, and a few more tips I’d like to share.
As with disassembly, If you’re using a spring retainer, it’s usually less of a hassle
to assemble the magazine while the receiver is stripped.
First, insert the follower, spring, and magazine plug if desired.
Installation of a new-style plastic spring retainer is simply the opposite of removal.
Place the retainer over the end of the magazine spring, and insert it into the magazine, lining
up the full-length slots with the dimples. Then, using a finger or screwdriver, push
it past the dimples, give it a quarter-turn, and let it back up.
When installed correctly, the retainer will stick out of the end of the magazine tube
about a quarter-inch, and won’t be able to rotate very much in place.
Once again, the older-style metal spring retainers are more of a hassle.
To get the retainer started in the tube, insert the side opposite the slot first, then squeeze
the two halves of the retainer together and work the other side in. Don’t be namby-pamby
with this, it will take a fair bit of force to compress the retainer and get it into the
tube. Once you manage to get it started, push it
further in so that it won’t pop back out or get in the way when reinstalling the cap.
The manual will tell you to tap the retainer in until it’s flush with the end of the
tube; but it’s way too easy to damage the end of the tube by hammering on the retainer.
Instead, press it most of the way in with your thumb or palm. Don’t worry too much
about pressing it in to an exact point, just get it in far enough for the magazine cap
to engage the threads. If the retainer needs to be deeper than this, it’ll get pushed
down when you tighten the magazine cap. Now once again, it doesn’t really matter
when you install the trigger plate assembly, but I’ve found that it’s easier to insert
and line up when the action bars and slide aren’t in the way.
Before reinstalling the trigger plate assembly, give it a once-over to ensure that everything’s
as it should be. The safety should be engaged, and the hammer
should be cocked. The sear spring should be in place between
the connectors and the sear. The carrier dog should be centered over the
carrier dog follower; and the carrier dog and carrier should both move freely.
The rear finger of the action bar lock needs to be underneath the left connector, and it
should push the connector up when the slide release is pressed.
Finally, the carrier pivot tube and the trigger plate pin bushing should be centered in the
assembly, and each should have a detent spring in one end.
Once the trigger plate assembly is ready to go in, insert it carrier first into the receiver,
and align the front tube and rear bushing with their respective pin holes. Then, insert
the trigger plate pins. As with disassembly, you can insert the pins
from either side, but if your detent springs are in their factory locations, it's easiest
to insert the rear pin from the right, and the front pin from the left.
Push them in until they engage the detent springs and sit flush with the sides of the
receiver. They should click into place without excessive
force, but you can give the pins a few light taps with a non-marring object if you need
to. If you can’t insert a pin all the way, check
to make sure your trigger plate assembly is properly lined up with the pin holes. If it’s
your front pin giving you trouble, you may have a displaced shell latch. See this video
for more information. Next, make sure the shell carrier is in the
down position, then slide the fore-end assembly onto the magazine tube. Set the slide assembly
on the action bars, place the breech bolt assembly on top of that, then line them up
and insert everything into the slots in the receiver until they stop.
This time, both shell latches come into play. First, hold down the right shell latch and
bring the slide back until it stops again. Then, release the right shell latch and depress
the left one, and bring the fore-end back the rest of the way.
If you removed the choke, put some oil or grease on the tube’s threads if they’re
dry, then screw it back into the barrel and snug it down firmly. Don’t reef on it if
you’re using a choke wrench; repeated over-tightening can severely damage a barrel or choke tube.
Before reinstalling the barrel, check the bore to make sure you didn’t accidentally
leave a cleaning patch or some other foreign object in there.
To reinstall the barrel, put the fore-end in the middle position, then insert the rear
of the barrel into the receiver, and slide the guide ring over the magazine tube. Before
you try to seat the barrel, look through the ejection port and make sure this cut in the
rear of the barrel is lined up with the ejector. The ejector is not an especially fragile or
breakage-prone part, but it’s not intended to stand up to a ham-fisted owner slamming
a barrel against the tip. If this breaks, the gun will be out of action until you or
your gunsmith orders and installs a replacement. Just take an extra half-second to line things
up properly, and you shouldn’t have any issues.
Now, without letting the barrel fall off – standing the gun on its butt end is a good way to do
this – reinstall your magazine cap or extension. If you’re using a cap, simply insert your
follower, spring, and any other components into the magazine tube – if they’re not
already held in place with a spring retainer – then tighten the cap against the barrel
guide ring. A firm hand-tightening should be sufficient, no need to crank on it with
any tools. If you’re using a single-piece magazine
extension, you can install it just like a magazine cap. But if your extension is the
type with a separate tube and coupling – like the factory Remington extensions – the coupling
has to be installed by itself first. Once it’s completely tightened against the barrel
guide ring, insert the follower, spring, and so on; then place the extension tube over
the spring, and thread it into the coupling. Tighten it down firmly, making sure not to
leave a gap between the tube sections. If you’re using a factory extension bracket,
slide it over the barrel and extension; again, bending it open if needed. Line up the bracket’s
screw hole with the groove in the extension tube, then replace and tighten the screw.
And with that, the gun’s back together. Point it in a safe direction and give it a
function check; either a basic rack & dry-fire, or by running some snap caps or dummy shells
through it. As always, I encourage any and all questions.
Firearms are complex pieces of equipment, so if you’re not sure what you’re doing,
consult your manual, ask questions, or get assistance.
I’m also open to constructive feedback, and topic suggestions for future videos. As
I mentioned at the start, this video wasn’t something I was planning to create until folks
started asking for it. If there’s another topic you’d like to see me cover, go ahead
and let me know. Until next time, please stay safe, have fun,
represent the shooting community in a positive light, and encourage others to do the same.