Mini-Me's Mossberg Shotgun Disassembly Guide

This is where you can talk about all equipment issues; firearms, ammunition, magazines, care & repair, holsters, gun cases, etc.

Moderators: Coordinators, Moderators

Mini-Me's Mossberg Shotgun Disassembly Guide

Postby evan price » Thu Jan 15, 2009 7:32 pm

This is a three-part article to show how a Mossberg pump shotgun is disassembled and cleaned up. Not every shotgun will need to be taken this far apart. If you are not comfortable doing this sort of work, it is best left to an experienced armorer or gunsmith, but really, there is nothing hard about the work. The gun used for this article was a "bargain-rack" junker bought for not very much money because it was in neglected condition. The barrel was brown with surface rust and had pitting at the rollmarkings. The entire gun was covered with greyish crud and the action was so stiff it took both hands to work it. The fired hulls would not eject unless you turned the gun sideways with the ejection port down. Sometimes it double-fed when cocked. Sometimes it did not feed a shell at all. The safety was stuck in the "fire" position. But generally, when a shell was loaded, it locked up, fired, and worked OK, and I didn't see anything that was actually BROKEN, just a lot of dirt, dried grease, and neglect. I did not include pictures of the barrel refinish or cleanup of the stocks because I didn't think to take any until afterwards. I hope that anyone who reads this finds it useful.


Image

Howdy, I'm Mini-Evan. Today I will be your guide as we explore what's involved in tearing down and inspecting a Mossberg shotgun. If your eyes are sharp, you'll notice this specific shotgun is actually a Western Field. These were distributed by Montgomery Ward under that brand name. Like Sears, Monty Ward didn't actually make any of their specific branded products, and they were made by well-known makers. This shotgun is actually a Mossberg M550A, which is a 12-guage pump with a 5-shell magazine and wood furniture. The M500, 550, 590, and 600 should all be pretty much the same as this, and the Maverick 88 models will be similar, with a few minor changes such as the lack of a tang safety (the safety is included in the trigger group as a cross-bolt style in the Mav88) and the method of attaching the foregrip to the action bars.


Image


The first thing to do before starting any work is to visually and physically inspect to make sure the gun is unloaded. Check it twice. Open the action and stick your finger in the magazine tube and chamber to make sure no surprise shells are left in there. If you're small like me, you can just climb on in and get a really close look...leave the action open halfway for the next step.


Image


To start disassembly, this knurled knob needs to be unscrewed. It is what holds the barrel on. Sometimes they are very tight and padded-jaw pliers might be needed. As the knob turns, you will feel clicking or notchiness. This is a series of grooves machined into the surface to act to lock the knob from unscrewing.


Image


Once the knob is spinning freely you will see that it is retained in the barrel lug and as it loosens it draws the barrel forwards. Once it is all the way loose, you can pull the barrel out of the receiver. Make sure the bolt is not closed since a lock lug in the bolt engages the barrel. Also depending on the shape of the foregrip you might need to move the action in or out a little to get clearance to lift the barrel off of the magazine tube.


Image


Once the barrel is off, set it aside. This is the magazine tube. It screws into the receiver with a standard thread. It must be unscrewed to remove it. Often this is very tight or may have sealant on the threads. The best way to get it broken loose without damaging it is to use one of those rubber pads used for unscrewing tight jar lids. If that won't work, padded-jaw pliers on the very end of the tube where it is welded closed on the barrel nut might work. Don't try this in the middle of the tube or it might dent.


Image


As you unscrew the magazine tube, be aware the magazine spring and follower are under tension. Keep a good hold on the magazine tube to prevent parts from explosively disassembling themselves. The follower will often be left in the receiver, and the spring just pulls out. If your gun had a magazine restrictor plug, this would be how to get it out.


Image


The magazine tube and spring pull out of the foregrip and the spring just pulls out of the mag tube. The follower only goes one way, the cup shape goes over the spring. I like to paint the end of the follower a contrasting color (besides black) to be able to better see if there are shells in the magazine. Since 12-ga shells are usually red, I painted this one blue.


Image


The foregrip is retained on the action tube by this castellated nut. With the magazine tube removed you have more room to get to it. A pair of needle-nose pliers or a strong flat-blade screwdriver applied sideways (or, the correct style wrench if you have it) unscrews this nut.


Image


The foregrip nut is off! The wooden grip just slides carefully forward to remove it from the action slide tube. Sometimes lacquer or crud makes it stick on the tube, just jiggle and pull and it should come right off.
"20% accurate as usual, Morty."

Striking down evil with the mighty sword of teamwork and the hammer of not bickering!
Carpe Noctem- we get more done after 2 am than most people do all day.
User avatar
evan price
Forum Janitor
Forum Janitor
 
Posts: 8832
Joined: Sun Jul 02, 2006 9:23 pm
Location: Westfield, Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby evan price » Thu Jan 15, 2009 7:55 pm

>Part II of Mossberg Disassembly Guide<


Image


The round thing in the receiver I'm pointing at is the trigger group retaining pin. It goes all the way through the receiver (and can be seen on either side) and keeps the entire trigger group in place.


Image


To remove the trigger group requires a pin punch. I find that the easiest thing to use if you don't have one handy is a common nail. If you're worried about scratching the end of the pin, file down the sharp tip. My experience is to go left-to-right and push the pin all the way out of the receiver.


Image


Here's the receiver pin, removed. There is a spring retainer in the trigger group that engages the groove on the end of the pin to keep it locked in there. Just pushing out the pin releases it, there's no funny business here.


Image


The trigger group tilts slightly up at the back, then slides a little towards the butt to disengage the front lip from the receiver. Then it just lifts out. Don't worry, it's all one captive unit and it won't kersplode when you take it out.


Image


This is the trigger group, removed. It's all one unit and it is not necessary to take it apart unless something is really wrong with it. If it needs to be cleaned, be aware that the main body is made of plastic, and any solvents or cleaners used need to be safe with plastic. An aggressive solvent may turn the plastic white. It might also turn it to goo. Generally a good brushing out and some gun oil on the moving parts is all this needs.


Image


Inside the receiver, a couple of parts may have fallen out when the trigger group was removed. The slots in the receiver they ride in need to be cleaned of old grease and dirt.


Image


The small bar of metal on the side of the receiver is the shell stop. It keeps shells in the magazine tube.


Image


This is the interruptor, it is the piece that goes on the ejection port side. It has a pivot that fits into a hole in the receiver. Its job is to prevent shells from double-feeding from the magazine tube.


Image


With the shell stop and interruptor out of the way, we can see this piece of metal. It is called the bolt slide. It is what links the bolt to the action bars and cams the bolt up to lock into the barrel when cocked. It can be lifted up, disengaged from the action bars, and removed. Make a note of how it goes in.


Image


With the bolt slide removed, you can now remove the action bars and slide. My friend here helps me with the heavy lifting and he wanted to be in a picture, too. The action slide & bars just pull straight out of the receiver. Check the bars' attachment to the slide for rust or looseness, I have seen the welds break once in a while. Also clean the slots in the receiver where the bars ride because these are dirt traps.
"20% accurate as usual, Morty."

Striking down evil with the mighty sword of teamwork and the hammer of not bickering!
Carpe Noctem- we get more done after 2 am than most people do all day.
User avatar
evan price
Forum Janitor
Forum Janitor
 
Posts: 8832
Joined: Sun Jul 02, 2006 9:23 pm
Location: Westfield, Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby evan price » Thu Jan 15, 2009 8:33 pm

>Mossberg Disassembly Guide Pt. III<


Image


This is the shell lifter. It is what drops down to pick up the shell coming out of the magazine, then lifts it up to the bolt. It should be fairly loose now.


Image


The shell lifter has two pivots, one on each side of the receiver, where I am pointing at.


Image


To remove the shell lifter, raise it up and squeeze it together until you can get the pivot pins out of the holes in the receiver. Then just lift it out.


Image


Once the shell lifter is out, the bolt assembly just pulls straight out of the receiver. You can see the two spring-loaded extractors (held in place by pins). Clean these so that they move freely. If they get crud trapped between the extractor and the bolt body, the extractor may slip on the shell rim and you get jams.
You can also see the firing pin. It should be clean and move freely in the bolt. The bolt ramps are what locks in to the bolt slide and cams the bolt up to lockup with the barrel when the action is cocked. It should also be clean. A little gun oil here will work wonders on how the action feels.


Image


This is the tang safety. The Maverick 88 won't have this. This safety is held on by the small flat-blade screw in the center. There is a small steel ball pressed into the receiver under the safety knob. It shouldn't come out, but it might. Before you remove the screw, look inside the receiver and see how the metal safety hook is pointing. I like to touch up the red paint in the safety "Fire" position.


Image


When the screw is unscrewed, the safety hook falls out.


Image


Here are the pieces of the safety: there is the plastic knob, there is a metal spring plate that is under the plastic knob (has holes in it), there is the screw, and there is the safety hook.


Image


This screw holds in a small metal piece which is the ejector. It is what pops the spent shell sideways out the ejection port. Remove the screw and the ejector should just lift right out of the slot it fits into. Take a look at this and make sure it isn't bent, that the slot isn't full of crud, and that the hook on the end isn't worn out. With the bolt removed, the ejector should be sitting with the end furthest from the barrel up higher than the slot. The ejector pushes down when the bolt moves past it, then springs back up to catch the rim of the shell and flip it out the ejection port.


Image


Here's the ejector. Check it over for cracks or wear. It should be fairly stiff but springy. Often a weak or worn ejector will cause jams as the spent hull does not leave the chamber. New ones are not expensive, and bending a worn ejector will only work for so long.


Image


To remove the buttstock, first you have to take off the recoil pad. This is usually held on by a couple of Phillips screws. Just stick a screwdriver in the holes in the pad and feel for the heads of the screws and unscrew them. You can see the screws in this picture.


Image


The buttstock is held to the receiver by a longish, largish screw. Some of them are Allen headed, most are straight-blade screwdriver slotted. You need an extra-long 1/4" blade screwdriver to reach to the bottom of the buttstock to remove the screw. Then, the buttstock just pulls off the receiver.


The receiver should be checked for damage, cracks, and wear. Ovaled shell-lifter pivot holes are possible. While the receiver is not stressed to chamber pressure in the Mossberg design, it is still possible to be damaged by mishandling or abuse. All the slots and grooves in the receiver should be cleaned and lubricated with gun oil. All the pieces of the gun should be cleaned and checked for damage or wear before reassembling. I have seen where action bars have had the spotwelds that hold them to the action slide break loose, usually from somebody trying to "Hollywood" the action (one-handed cocking by flinging the gun up and down) or on heavily used & poorly maintained guns. It's normal for some side to side slop on the action slide as it sits on the magazine tube, and some twisting looseness is normal.

Re-assembly is the reverse of dis-assembly. Use caution and function test the gun after putting it back together before you put it back into service. I use a couple trimmed, empty shells to test for feeding and function before using live ammo. Above all, check the function of the safety and trigger parts to not fire if bumped, slammed, or banged.

The Mossberg pump is a simple, durable gun, and if maintained properly, will provide years of service.

Happy shooting.
"20% accurate as usual, Morty."

Striking down evil with the mighty sword of teamwork and the hammer of not bickering!
Carpe Noctem- we get more done after 2 am than most people do all day.
User avatar
evan price
Forum Janitor
Forum Janitor
 
Posts: 8832
Joined: Sun Jul 02, 2006 9:23 pm
Location: Westfield, Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby evan price » Thu Jan 15, 2009 9:18 pm

Is that enough pictures??? :lol: :lol: :lol:
"20% accurate as usual, Morty."

Striking down evil with the mighty sword of teamwork and the hammer of not bickering!
Carpe Noctem- we get more done after 2 am than most people do all day.
User avatar
evan price
Forum Janitor
Forum Janitor
 
Posts: 8832
Joined: Sun Jul 02, 2006 9:23 pm
Location: Westfield, Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby ArcherAce » Thu Jan 15, 2009 9:29 pm

Nice write up, Evan. But, you've got some frickin' issues, man... :lol:
"Being nice is something stupid people do to hedge their bets."
User avatar
ArcherAce
 
Posts: 4634
Joined: Wed Aug 10, 2005 3:16 am
Location: Toledo

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby Jake » Thu Jan 15, 2009 9:29 pm

Hysterical...yet informative.
:lol:
Howdy, I'm Mini-Evan.
Full size Evan may be scarier than I thought. :shock:
Last edited by Jake on Thu Jan 15, 2009 9:34 pm, edited 1 time in total.
NRA Certified Instructor: Pistol
NRA Certified Range Safety Officer

Hope for the Best. Plan for the Worst.


http://www.salemhuntingclub.com
http://www.nraila.org/get-involved-loca ... -reps.aspx
User avatar
Jake
OFCC Coordinator
OFCC Coordinator
 
Posts: 11311
Joined: Fri Apr 14, 2006 11:04 am
Location: N.E. Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby Morne » Thu Jan 15, 2009 9:33 pm

Thank you, very informative. :)

But boy-howdy, cabin-fever has sure set in. :shock:
Thus spoke Zarathustra.

Footsoldier in the Conservative Insurrection of the GOP.

Remember, only you can prevent big government!
User avatar
Morne
OFCC Director
OFCC Director
 
Posts: 10443
Joined: Thu Jul 07, 2005 9:01 pm
Location: Wayne County

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby dan dan the XD40 man » Thu Jan 15, 2009 9:46 pm

This thread is pure WIN!
Poop!
User avatar
dan dan the XD40 man
 
Posts: 8370
Joined: Mon Dec 26, 2005 9:49 am
Location: Cleveland Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby Mr. Glock » Thu Jan 15, 2009 9:48 pm

Next, do it in Claymation.....
“Without dignity there is no liberty, without justice there is no dignity, and without independence there are no free men.”
- Patrice Lumumba
OFCC Patron, NRA Benefactor Life, GOA & Hot Stove League Member
User avatar
Mr. Glock
OFCC Patron Member
OFCC Patron Member
 
Posts: 8624
Joined: Wed Nov 01, 2006 3:20 pm
Location: NE Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby ArcherAce » Thu Jan 15, 2009 9:49 pm

OOOOOOooo!!!! Do a Robot Chicken version!
"Being nice is something stupid people do to hedge their bets."
User avatar
ArcherAce
 
Posts: 4634
Joined: Wed Aug 10, 2005 3:16 am
Location: Toledo

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby sodbuster95 » Thu Jan 15, 2009 10:23 pm

ArcherAce wrote:OOOOOOooo!!!! Do a Robot Chicken version!


HA! +1! :lol:
NRA Benefactor Life Member

Information posted in these forums is my personal opinion only. It is not intended, nor should it be construed, as legal advice.
User avatar
sodbuster95
OFCC Patron Member
OFCC Patron Member
 
Posts: 6738
Joined: Mon Dec 01, 2008 5:14 pm
Location: Maumee

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby River 447 » Thu Jan 15, 2009 10:55 pm

We may have a winner for the “Way Too Much Free Time” Award.

Nice write up............but really great photo/story.
River 447
River 447
 
Posts: 474
Joined: Fri Oct 27, 2006 4:16 pm
Location: Sullivan, OH

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby 1/2 Fast » Sat Jan 17, 2009 2:38 pm

Great post!
Now I'm off to Toys R Us to pick up the few items still missing from my cleaning/gunsmithing supplies. :wink:
NRA Member
User avatar
1/2 Fast
 
Posts: 548
Joined: Sat Sep 01, 2007 8:21 pm
Location: Just far enough from Cincy

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby Brian D. » Sat Jan 17, 2009 3:05 pm

I want to see the 'extras' DVD--where mini-Evan goes flying across the room a/k/a "Mr. Bill" of Saturday Night Live fame, when he can't control the pressure of that "massive" magazine spring!

We need some sort of awards program here at the forum. (The 'OLTCACHies'? )Evan would be a shoe-in for Best Instructional Thread and maybe Best Cinematography. :lol:
Quit worrying, hide your gun well, shut up, and CARRY that handgun!

********************************************************************************
1911 and Browning Hi Power Enthusianado.
Brian D.
 
Posts: 14644
Joined: Mon Jul 04, 2005 8:42 pm
Location: SW Ohio

Re: Mini-Me's Mossberg Shotgun Disassembly Guide

Postby Gumby » Sat Jan 17, 2009 4:43 pm

Mr. Glock wrote:Next, do it in Claymation.....

Definitely claymation!!
(wish I knew how to insert my Gumby picture!)
Wow - very thorough and informative.
Gumby

"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government." -- Thomas Jefferson
User avatar
Gumby
 
Posts: 359
Joined: Fri Dec 05, 2008 7:51 pm
Location: DAYTON, OH

Next

Return to Firearms & Gear

Who is online

Users browsing this forum: No registered users and 6 guests