I don't have a clue but someone will. Welcome to MarlinOwners!

 

I've only seen one, a few years ago but condition was poor so I passed, still lookin'. This gun was 12Ga, had the Marlin adjustable choke and was ported, the choke was called "Micro Choke", the gun had no serial # so it would have been pre '65.

 

I have a Mod. 55 with a 28" barrel, Micro-choke and ported barrel, no serial number. It was made in New Haven (pre 68) and I bought it after High School (66), so lets say it was 67. I got it courtesy of a Marlin executive, he said it would shoot 3" shells, although it doesn't have 3" stamped on the barrel.

 

They do have 3'' chambers, never could figure out why they never got marked that way.

 

I have one. The poly choke was horrendous, it squeezed the choke unevenly and the point of impact rotated around the point of aim when I adjusted the choke. Mine is lemon that I turned into lemonade. I cut the barrel to 20" which removed the choke and ports. Then I machined a scope mount that held the scope at the 11 o'clock position in order to clear the bolt. Then I free floated the barrel and bedded the receiver with polyester resin. It isn't pretty, but it's one heck of a slug gun.

 

Nice, my kinda' shotgun, I did something similar with an old Savage Stevens 20GA bolt gun. I'd post pic's but when I get the film outta' my 35mm I can't find where to put it in my computer. :biggrin:

 

Centaur 1 - I see your gun crop up all over on the internet as I'm usually searching for sighting mods for my Goose Gun as a card shooter. May I ask you a couple questions about it?

First and foremost I want to go to a blade sight. It's not in the pictures above, but I know you fabricated one yourself. Did you look at replacement part blade sights from 55/512 slug guns and they didn't work out, or you just fabricated something from scratch right out of the box?

Secondly is your rear peep sight. It's very unique looking compared to others I've seen. I got the Lyman made for it, and it's a very much shallower affair front to back. Was yours purpose fit for the 55, or something you put together yourself?

 

I modified my gun about 1980, before the 512 existed so machining a sight was my only known option. I turned two brass rings with just enough clearance to fit over the barrel. Then I milled the front sight and machined two steps for the rings. I made a fixture to hold all three parts in alignment and silver soldered them together. After they were soldered together I drilled two holes for set screws to hold the sight assembly to the barrel. The peep sight is the Lyman sight that was made for the 55. I was getting glare on the peep so I turned an insert that was deeper to shield the aperture from sunlight.

 

Thank you for the response!

You're quite the machinist - more than I could possibly do, which is just about nothing more challenginng than buffing and grinding. The knurling on that sight insert is a true work of art.

For now I have one of the fiber optic slip on sights for the front, but I'm hoping for a more refined look. I think I'm just going to order the 512 pats and see what happens from there.

Thanks again for the reply and for sharing the work on your great gun!

 

And to the original poster...

Although I've had my 55 since like April, for some reason I just like looking at them enough that I kept the gunbroker email alert active for them, which today turned up this fella. Not perfect, but looks like potential for a TLCer.

Marlin 55 12ga Bolt 24" Poly Choke-Micro Choke bbl : Other Shotguns at GunBroker.com

 

Centaur, thats outstanding work, bet you could sell a million of those front sights if you could make it adjustable.

 

Thanks for the compliments, now that I'm retired I really miss being able to make stuff like this. 20GA, one of the cool things about having the proper equipment, is the ability to machine things to the exact size needed. I was able to measure how tall the sight needed to be and machined it to that size. Years ago my dad was a cop and he carried a S&W model 19 when he was off duty. He was always knocking the flimsy adjustable rear sight out of alignment when putting the gun in and out of his holster. So he sighted in the gun and I took it to work with me, then I took measurements of the sight and the gun. I was able to machine a fixed sight for him that couldn't be knocked out of alignment.

khigh, would something like this work? "MASTERPIECE" BANDED FRONT RAMP | Brownells

 

Those would be great, thanks, but unless I'm overlooking them I only see rifle diameters.

 

The bottom one on the list will fit a barrel with an outside diameter of .827", that's only .010" smaller than the barrel on my 55. It's my understanding that a gunsmith will order the barrel band that's the next size under the barrel, then open the hole up to fit the barrel. Make it so you get a tight fit, might have to tap it on the barrel with a plastic mallet. Once the sight band is in the right spot and lines up with the rear sight, heat the barrel and the sight with a propane torch or a heat gun and when it gets hot enough try and get some silver solder to flow between the barrel and the band. If the fit is tight enough I bet you can use locktite to hold it on the barrel.

One observation I made with my Marlin 55 smoothbore slug gun. There are a lot of slug brands and styles to chose from. As great as they work from a rifled barrel, the smoothbore 55 is limited to foster style rifled slugs. While some brands of slugs are extremely accurate, some just plain old suck. I'm sure that manufacturing processes have changed in the last 20 years since the last time I used my 55 to hunt. The winner back in the 1980's was Winchester, at 100 yards the holes would touch or be really close to touching. Federal slugs also worked well enough to hunt with, at 100 yards I could hit a gallon milk jug. Won't win any shooting tournaments, but if you shoot at a deer you'll hit it. The worse slug was Remington, 5 to 6 foot groups were the norm with my gun. Funny thing is my hunting buddy uses a Beretta semi-auto with a fixed modified choke. He shoots those Remington slugs and they are the most accurate in his gun.

One nice thing no matter which type of slug you use, they make a HUGE hole that lets a lot of blood escape.

 

Mine's not for slugs. It's for turkey shooting/card shooting. At the level I compete at, it's not really an exact science, even bad shooters can win, but it's fun to fix up a gun Some guys put scopes and even red dots on, but I like things a little old school.

If I can get a dovetail ramp on the front, I could go this route.

Front Sights, globe - Track of the Wolf

 

So much great info on this site, even an Old Phart like me can learn a few things.