Thursday, August 9, 2012

The Saga of the WesternField Shotgun Part One

Every once in awhile opportunities present themselves in irresistible ways. Those opportunities are almost always troublesome, but have a way of working out in the end. A couple of weeks ago, such an opportunity presented itself in the form of a Westernfield shotgun  A friend of mine approached me saying he had a friend that wanted to sell an "old store brand 16 gauge pump action shotgun in pretty good condition". With a $50.00 price tag on it I knew that if the gun really was in decent condition, that was an unbeatable price, so I told my buddy I was interested in seeing it.A few days later I get a phone call from my buddy saying he has the gun, and he wanted to bring it to me to look at.When he gets to the house he hands me a Western Field M550B 16 gauge pump action with a six shell capacity and an adjustable choke.
Westernfield M550B 16 Gauge  (Mossberg 500B) 

Some Fancy Scrolling
PolyChoke Adjustable Choke
Not Bad For 45 Years Old + or - 
A quick inspection revealed a few small rust spots on the barrel, and a couple of small scratches on the stock from being moved around in a closet for (at that point) an unknown amount of time, and a thin coat of a really sticky grease on all of the moving parts and the threading of the adjustable choke. Even the finish on magazine tube where the forearm rubs showed very little wear from it being cycled. This gun looked like it had been bought and put into a closet  never to be thought of again with the result of leaving it in near showroom condition. I didn't think twice about handing my friend the full asking price and took possession of the shotgun with the plan of cleaning it up a bit and selling it for a quick profit.

Before going to the local gun shop to sell the shotgun I wanted to test fire know...for research make sure....oh okay, I just wanted to hear the thing go KABLOWY a few times! after all, I did spend my hard earned money on it. A quick trip to Walmart for some shells and a phone call to my brother and I had a Saturday morning set up to take a ride out to a nearby open desert area to shoot of some shells, but first the gun has to be cleaned and oiled. I still didn't have any idea how long this thing has been sitting in a closet and I wanted to make sure it was safe to use. The wife was going to a movie with a friend so I pulled out the old cleaning kit and got to work.

Like most other shotguns I have dealt with in the past the barrel is attached by a knurled hand screw that goes into the end of the ammunition tube. A few quick turns, a half cock, a small tug, and it came apart real easy. That is where the similarity with the others ended. After removing the barrel I couldn't get the forearm to come out of the chamber until (after a lot of head scratching and a few choice swear words) I notice that a plate was holding the bar in place. The plate was held in by the trigger assembly which comes out by removing a single retaining pin. After I get the trigger assembly out I turned the gun upside down to get the plate out, and parts fall all over the table. after another series of expletives I pick up the plate and two funny shaped pieces of metal that are curved at one end. Now the forearm pulls out smoothly, and the bolt assembly comes out the hole left by the barrel. I have always been pretty good at taking things apart carefully. That way I know exactly how they go back together, but I didn't see how those two pieces of metal came out. I tend to think of myself as a reasonably smart person, so being confident in my limited gunsmithing abilities I decided it wouldn't take much effort to figure out how to put it back together and I got to work with the cleaning.

A thick yellow sticky grease like substance covered all of the small parts and made the inside of the barrel tacky and difficult to get clean. After an hour of softly scrubbing with gun solvent, cleaning patches, and oiling everything up, I looked around at all of the shiny bits and pieces and decided I was done cleaning. Even the few small rust spots on the barrel and ammo tube were barely visible. I took a fresh patch with some more gun oil on it and gave everything one more coat of oil and then wiped the excess off with a clean patch and start to put the gun back together. This is long about the time my wife comes through the door and asks me "how much longer are you going to be?" without hesitation I reply that all I need to do is put it back together which shouldn't take long at all. so she goes and sits on the couch and starts to watch TV.

Two hours later my wife has long since gone to bed, and I am getting an online education on the history of the Westernfield name and how it links into the Mossberg 500 family of shotguns. I did manage to get a good idea of how old this gun was by finding out that Mossberg started manufacturing this gun in 1962 and serial numbers weren't required by law on long guns until 1969. Because they weren't required by law and had to be hand stamped at the time Mossberg didn't put them on in order to save a little on production costs. My gun doesn't have a serial number so by default it has to have been made in that time frame.When I finally find a diagram of how the inner workings go back together I want to smack my head against the wall for being that stupid. I had been trying all night to fit a long thin curved piece of metal in between the bolt and the sliding plate that holds it and the forearm bar in place, but it doesn't go there. It slides into a groove along the side of the chamber where it helps keep everything in place.Ten minutes later I have everything cleaned up and I head into bed for the night excited about the morning's shooting trip.

Part Two: The Test
Part Three: The Repair



  1. I also just purchased the same gun. I can't get the trigger assembly put back together. Cant figure out where those 2 springs go. Any help or a link to a schematic would be great. thanks

    1. The schematic that helped me out was at Numerich Gun Parts Corporation. Go to click on the M in the search by manufacturers block on the right hand side then click on Mossberg then scroll down to the shotgun section and click on the "parts list" link for the 500.that should bring up a fairly detailed exploded view of this style of shotgun. The direct link is This will give you a good idea of where things go inside the shotgun. They also have a PDF file you can download for $1.50. If that doesn't help you out I would go over to They are the official "Mossberg historians". Vic over there actually wrote a book on the entire history of the Mossberg corporation. Send them an e-mail, they may have something more specific to your particular gun. Be prepared with your guns serial number, that will tell them every thing they need to know about it to get you going. In my next post I will tell you all about how i found all of this out. ;)

    2. YouTube it mossburg 500 assembly

  2. Hi! I am really interested in one thing, of course if that's not too much to ask could you please share with us where you grew up?