Finally Started On My Old Mossy Project

[Cosmoline]

I've had the parts of a very abused Mossberg 500AT in a bucket for a few months. I soaked the metal innards in cleaning solution for awhile, scrubed them down twice and annointed them with CLP. I had to take some steel wool to the exterior of the shotgun. I finally had some time tonight and put it all together, with a new folding tactical stock and a ported slugster barrel.

The stock is one of the new Knoxx "Copstocks" and is very different from the Butler Creek sidefolder I had on my old Mossberg. It's supposedly designed to absorb recoil, which was always a problem with the Butler Creek.

The tactical light is a standard Surefire attached with a $5 part designed to secure shotgun magazine tubes.

Still to do--replace the forend with a leaner black plastic design and install the rear sight on the slugster barrel.

 

[Dave McCracken]

Nice project gun. A couple things....

Folders are not my choice, though others like them. On a Mossie, they may impede using the safety. Test a few times and see.

Also see how well that light position works in fast handling.

Get some range time in soon. If everything works out you've got a great shotgun...

 

[Cosmoline]

This folder is strictly for storage purposes. I'd be insane to fire magnum slugs without the stock in place. I am very curious to see if it reduces felt recoil as they claim. I'll take it out to the range this weekend and give a report. So far the only problem is it does make it difficult to reach the release toggle without changing your grip.

 

[CaCrusin]

Trust me!

The COPstock is the only folding stock I would ever put on a shotgun and that's not because I work for Knoxx. When you take it out, try these two tests:

1) Load it with the heaviest slug load you have and fold the stock. Hold the shotgun out with one hand and aim it like a handgun. Shoot at a target 25 yds away and see how little recoil there is and how accurate you can be.

2) Again with heavy loads, fold down the wire frame and hold it gently agains your shoulder. Grip the pistol grip firmly in your storng hand and fire the shotgun. Pulling the stock tight against your shoulder does not reduce recoil. On the COPstock, it makes it worse.

Then write up your results, I think you will be pleasntly surprised.

CaCrusin

 

[scout26]

MMMMMMmmmmmmmm.....Caraway crackers.......

 

[Cosmoline]

You can also use Finncrips to remove light rust. For heavier corrosion I use Swedish Knackbrood

 

[scott.cr]

Brownells sells the synthetic forearm for $21.95 (p/n 631-000-251).

IIRC most of the wood forearms use the shorter 6.75" slide tube; with the synthetic forearm you'll need the longer 7.75" slide tube, p/n 631-000-023, $58.59.

For that much hay you might consider getting a Surefire Picatinny forearm and putting a front grip on it so you can be 100% tacticool.

 

[albanian]

How long is that bbl? You either need a shorter bbl or a long mag tube to make it look right.

I just bought a Knoxx CopStock for my Rem-870 HD. I tried it out and it does absorb recoil. I could fire one handed holding only the pistol grip with no problem. I don't know exactly how it works but there is a spring in the grip that has something to do with it. I don't really like the stock because it messes up the pointing virtues of my 870 but for a tactical shotgun, it looks good. I am probably going to take it off soon.

 

[Cosmoline]

The barrel is a full 24", which I agree is a bit long. I'm still on the hunt for a true 18" slugster with sights. If I can't find that I'll just get the standard full choke short barrel with a bead that Mossberg sells.

 

[Cosmoline]

I've run an array of loads through my current setup and it's pretty impressive. That Knoxx stock really does reduce the recoil, as does the porting on the odd ball slugster barrel. The net result is I can fire off magnum 3" Brennekes with less felt recoil than my Mosins. The only drawback is the stock's left pylon is a horribly cheek rest for shooting the sighted slugster barrel. It smacked my teeth a few times. I'm solving the problem by wrapping it with a thin layer of springy bandage tape topped by duck tape. A little bit should resolve the problem.

 

[Cosmoline]

Update. After more messing around than I had anticipated, I've finally completed the new 500: "Magnus" I'm naming it after a Swedish ancestor of mine.

Finding a new forend grip proved difficult as the Mossberg was one of the old style and had different dimensions than the new ones. But I found an ATI pistol grip forend that had adapters for both types. It's not as nice as the Copstock pistol grip, but then again it doesn't have to absorb the same level of recoil stress.

You can see I added a thin layer of electrician's tape to take up some of the slap against the cheek. It's OK though I prefer to toss a rag over it for additional protection.

The bandolier is from Blackhawk and is similar to the ones Cabela's sells. I use it to keep my shells together. Otherwise they tend to wander and end up in odd boxes.

The barrel is an 18" slugster with rifle sights from Numrich.

The cycling rate is VERY fast and the whole platform extremely stable. It's entirely possible to fire off multiple magnum shells from the waist. Unfortunately I didn't finish it in time for this year's salmon season, but Magnus will be there next year for sure. In the mean time I have some low-recoil home defense slugs for it.

Total cost was about $350 total including the shotgun, new barrel, heat shield, Copstock and foreend grip. I wasted some money along the way due to my mixup on the length of the foreend, but that just means a bigger parts box so no big deal.

The magazine is pretty worn out so I may replace that in the future, but for now it's working fine. You can see the blue has been scraped off of some of it.

 

[akanotken]

The COPstock is the only folding stock I would ever put on a shotgun and that's not because I work for Knoxx. When you take it out, try these two tests:

1) Load it with the heaviest slug load you have and fold the stock. Hold the shotgun out with one hand and aim it like a handgun. Shoot at a target 25 yds away and see how little recoil there is and how accurate you can be.

2) Again with heavy loads, fold down the wire frame and hold it gently agains your shoulder. Grip the pistol grip firmly in your storng hand and fire the shotgun. Pulling the stock tight against your shoulder does not reduce recoil. On the COPstock, it makes it worse.

Then write up your results, I think you will be pleasntly surprised.

CaCrusin

CaCruiser,

Should the same hold be used for the specops stock as well?

Forgot to add, Nice looking Shotty Cosmo!

 

[CaCrusin]

CaCruiser,

Should the same hold be used for the specops stock as well?

Forgot to add, Nice looking Shotty Cosmo!

Absolutlely.

I like it too.

CaCrusin

 

[Cosmoline]

Added the tactical light mount and light:

After some more range time I also bolstered the front grip with padding and electrical tape. On magnum shells the mossy likes to kick the bolt and slide back which can be painful if you don't time it right.

All that's left now is a sling.