hkcavalier's Mossberg 500 Fowler Project

From time to time I bring in other gun owner's projects, as a way of keeping my readers entertained with new content.

The author of this post needed a shotgun for hunting and did not want to put down the required quatloos to purchase a new gun.....so he built one. He goes by the screen name "hkcavalier".

This is a similar build to me Sears/Winchester shotgun project. 

Here is the project in hkcavalier own words and pictures:

Background: Last year my elk hunting buddy says, "Hey you want to hunt some birds during the middle of the day and chase elk in the morning and evening?" Naturally this was after I had driven across the state with my elk rifle and nothing else. So we unsuccessfully hunted birds, me with a loaner Model 12 that was old when my dad was born, and barely worked.

For this upcoming season I wanted my own working bird gun! Yes I could head down to Big 5 and get a brand new Mossberg 500 with spare 18.5" barrel for $340 plus tax. But I'm both cheap and stubborn so decided to build my own. One of the guns we tried to get working to hunt with was an older 500, but the slide tube was completely stuck to the magazine tube. This last Spring I bought it off the owner for $75 knowing I would have to replace some parts.




Here's what the receiver looked like:

I Dremeled it smooth but there was just too much material missing. I put a "notify me" with GunBroker for Mossberg 500 receivers, the first one that came up that I liked was Duracoated in flat dark earth. This was a bit darker than what I thought I wanted for the gun but thought, "Hey one less thing to paint!" .

I broke the original gun ALL the way down...I mean every part, screw, etc, even the trigger assembly which was full of rusty lube.

Turned out the mag tube and slide tube assembly were both shot, there is a split metal piece on the older guns, if it breaks free and gets bound up you will destroy both parts getting them unstuck. So I ordered up a brand new mag tube from Midway USA.

I DO NOT recommend breaking the trigger assembly all the way down! The whole thing is a pain to get back together, I was saved by YouTube videos and the fact I already own a 500 Persuader and could compare. I wanted to coat the parts for rust reasons, but through operation the gun will strip much of that right off.

A fellow forum member helped me big time with new parts at great prices. From him I picked up a black plastic stock set, slide tube, and magazine spring.

The Gunbroker receiver came stripped...Two parts were tough to find: the safety spring and detent ball. I'm stubborn. Dremel and a chisel will get you what you want! (removed from the old receiver)

 
I have used Brownell's Alumahyde FDE in the past and thought it would work great. So...of course...Brownell's was out of stock with a distant expected stocking date (their FDE is confusingly called Coyote). I thought, "Desert Tan will be pretty close and will hide well in the brush." So I ordered a can of that plus Semi Gloss black to coat the action parts.

The bolt and bolt guide were both really worn so back to get more parts, again from my fellow forum member who had both plus an elevator, all parkerized.

Here's my "painting station" for the barrel, mag tube, and slide tube assembly. This is a piece of scrap wood from Warmoth Guitars in Puyallup and worked perfect.

 Here's the finished product after painting and assembly. Ignore the plug for KIX, my project room doubles as a pantry! The top of the rib is brush painted in flat black enamel.

 So yeah...the FDE and Desert Tan don't match much at all, but I like it, everyone will know this is a "bubba" gun, as long as it works I'm happy. I'm not Doug Turnbull!

Here's the safety and follower, Glow Orange enamel is handy, my jar is left over from re-doing the safety paint on a CZ-52. Older gun with steel safety and follower, nice stuff.

I had to Bubba the handguard for some reason, it was too short to reach the mag tube nut. Had to hack a plastic part I had laying around, it actually works great. I tried the Hogue extended nut, but it actually is longer in the wrong direction, toward the muzzle.

Fitting the parts was tough, these are parts from 4 different guns (plus a few new factory parts) after all. 
The cartridge interrupter (the long steel piece that hooks the lip of the shell) wouldn't reliably get a shell, so after some trial and error with a vise it works great.

Since paint adds to each dimension, working the action will wear it off. Alumahyde is tough but steel on steel will take it off. You can see that on the elevator and where it's coming off on the action bars. Since this isn't a show piece I don't really care, but it's good to know.

This became a Froglube gun from the get-go. I found the parkerized parts soak up the Froglube like crazy while the smooth parts get nice and slick. After this, I am of the opinion that Froglube is best for tight, smooth guns like my Kimber Solo, not a rough gun like this one. I had to overuse the paste just to get it slick enough to not scrape. I am sure I will be pulling aluminum dust and Alumahyde bits from this action for some time.


Cost of the project:
Old 500: $75 (this gun contributed the 30" full choke barrel, trigger assembly, safety, a couple of action parts)
Receiver: $85 (includes transfer fee)
Mag Tube: $35
Slide tube / spring / stock: $50
Alumahyde: $30
Bolt, bolt guide, elevator: $70
 
Total: $345

So like many projects, I didn't come out ahead financially, but I certainly learned a ton about the 500. Most of the parts are superior to a new production "bird gun" 500 and this gun is a lot more weatherproof too.

The Author thought that was the end of the project, but he was mistaken....(boy do I know what that is like...)

Might be hard to tell, but the barrel now almost matches the receiver. I painted the magazine tube black since the slide tube will strip off paint/finish. A light color just looks bad when that happens. Same with the action bars, they get covered with crud and get gray/black anyway, don't paint them a light color.

I might end up doing up the forend and stock in FDE (Brownell's Alumahyde "Coyote"). Any ideas of how to prep plastic?

Also, ended up de-Froglubing the entire gun and going with petroleum-based grease where it slides and lighter lubes elsewhere. Replaced the very tired hammer spring with a new factory one and that seems to have fixed all my misfire issues.

Bubba gunsmithing is both frustrating and rewarding at the same time!



I still didn't quite like the gun and just had to play with it some more. Originally the plan was to find an 18.5" "riot" barrel, paint it, and have 2 barrels. But the more I looked around, the more I realized that I'd be better off getting a more modern adjustable choke barrel and sawing off the 30" full choke barrel.
So I won a nice 28" Accu-Choke barrel with a little rust here and there on Ebay. Painted it up and slapped on a Tru-Glo Fat Bead. Unfortunately I overtightened it and cracked the fiber optic in the middle. Why there isn't metal in between the screw and the fiber optic is beyond me. One of those "I assumed it would be that way simply because it doesn't make sense to do it any other way" moments.
This week I took a chop saw to the 30" barrel. It was an educational experience as my brother in law warned me not to take it below 16" --- I let him know it's actually 18" for shotguns measured at the very back end of a chambered shell. The way the ribs were it wouldn't have looked right at 18.25" or 18.5". I cut it off right at the last "legal" rib which is just over 19". hkcavalier's cornhole is safe from federal PMITA prison.
It needed a new bead sight hole threaded so off to McLendon's Hardware for a 5-40 NC bottomed tap. Very easy in the soft steel of the rib. A drill press and center punch are pretty much the only way to go for the pilot hole. It looks no different than factory. Well, 'cept for a rib on a short barrel.
Sanded the muzzle and made sure all burrs were gone. Then, more Alumahyde. I primed and painted a thick bead sight with green marking paint which only worked so-so. It was too soft, even cured, and when tightened some wore off. We'll see if I want to keep it, it's not very useful.
The two-tone barrel scheme is the result of: running out of FDE