Making a button mag / half magazine

[Carlsen Highway]

I have been toying with the notion of getting a 24 inch octagonal barrelled Rossi 92, and then cutting the magazine down to the end of the foreend, a button mag / half magazine rifle.

Many people dont care for the look of the short magazine, my father hates them for example, and I do not care for them on a carbine (they are common encountred over here) but the octagonal barrel on a Rossi rifle looks too big or thick to my eyes, and I think just having the barrel and no mag would improve things as well as make the rifle lighter, and probably more accurate. And teh old school lever action as a sporting rifle with an octagonal barrel, well, I like the idea. I would checker it too I think, and put a tang sight on.

But how are these constructed? I was thinking I could just take the magazine tube out, cut it shorter at the receiver end, but what keeps the magazine fitted if its not got a screw at the end hold it to the underside of the barrel?

[GunnyMack]

I would bet the receiver end is threaded and that would either need to be rethreaded or you need to cut the muzzle end.

[Pete44ru]

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I converted one of my round barrel Rossi Model 92's to a button mag, several years ago.

I used a $1.29 hacksaw, to shorten the issue mag tube (which is a sliding fit into the front of the receiver opening) from the rear; $4 Chinese milling machines (files) to cut a female dovetail in the barrel bottom to accept the forend cap hanger (aka: forend tenon); and my plastic to buy the forend cap/hanger & screws from a parts house (Numrich, Wisner's, etc) for about $17.



The extra parts needed will be a button magazine end (which has a flange that used to retain the magazine tube in the forend cap), a button mag forend cap (which has an internal groove that accepts the flange around the special magazine end described earlier), a forend tenon/hanger, 2 FE cap/tenon screws, and some means to fill in the blanks in the bottom of the forward end of the barrel after the magazine tube is shortened.

Since the Model 1873 has an octagonal barrel, those parts can be used for your Model 92, since those Model 1892 parts are relative unobtainium.




The hardest part of the job is determining exactly where on the barrel bottom the centerline of the new dovetail slot for the forend tenon will go, since you're going to work outwards in both directions from that C/L until you have a 3/8" width (or whatever) female dovetail. (measure 5X, cut 1X)



After the location of the dovetail C/L is determined, you will generally need to make a square/level notch in the bottom of the barrel, then expand the lower inside edges of the square notch outward (forward & rearward) until a 60-degree female dovetail is achieved.(below)

NOTE: The procedure is the same for both round & octagonal barrels.

HINT:: I applied a single layer of yellow masking tape to the barrel, and made my marks on the tape with a pencil, so I could see my mistakes.( I made a few, but they were erasable)


Once the female dovetail cut C/L is located, make 2 marks, one on either side of the centerline (on the masking tape), a distance apart from each other equal to just UNDER half the measurement of the NARROW part of the male dovetail, of the sight or tenon that will be installed in the female dovetail.
That will define to top of the open dovetail, once you're done, with an allowance for fitting.

For cutting the female dovetail, clamp the barrel, marks UP, in a vise, & plumbed so that the dovetail will be level across the barrel's width.

Make two vertical cuts down into the barrel, one cut at each of the outer marks, to a depth just shy of the depth of the male dovetail you have (to allow for later fitting), from the narrowest part down to the widest.
Follow up with as many secondary cuts as you can between the first two cuts, to remove the bulk of the "meat". (I used a hacksaw for all of this)






Now, with a file, clean up the notch in the barrel so that you end up with a square, LEVEL (side-to-side, AND front-to-back) recess in the barrel, that's almost as deep (but not quite) as the male dovetail of your sight, forend tenon, etc.

I then start to cut into each sidewall of the square/female recess, a little at a time, with a small triangular file held with one of the file's flats on the bottom of the recess.

NOTE: Take care to keep from cutting into the floor of the recess with the bottom/flat of the file, while filing out the sidewalls to the 60-degree angle needed for the dovetail.







STOP, when the bottom/wide part of your filing starts to encroach upon the first two top markings you made earlier, and try the male dovetail for fit.



Now the fun starts - file a very little bit, try, file, try, file, etc - until the male dovetail starts to enter the recess.

I would strongly advise against beating it in, since a good/tight fit can be achieved with some thought and careful filing/stoning.






I also re-used the issue forend wood, but I had to slightly rasp down the forward couple inches of the forend wood, to be flush with the new forend cap, then stain the area to match the rest of the FE, and apply stock finish to the alteration area.

(EDIT: Doh, I forgot (thanks, Griff) - shorten the existing magazine spring to a free length equal to 1-1/2 X the length of the shortened magazine tube, for optimum feeding.)

Be sure to take pics as you proceed, since the pics I had posted in my years-ago thread, detailing the work & finished look, disappeared when the pic hosting website I used back then went belly up.

Have a good time working on your rifle - AND remember: If you mess up, you can always buy new/original parts & put it back in the issue condition.


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[AJMD429]

Pete44ru gets the prize for most awesome 'how-to' post of the month. ....!

[Carlsen Highway]

Pete, an absolutely fantastic post and exactly what I needed to know. Thank you very much.

[M. M. Wright]

Thanks Pete, that's good info.

[Pete44ru]

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You're entirely welcome, folks.....

I've always thought that maybe others won't have to make the same mistakes I did, while noodling "stuff" out.........


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[Griff]

If you're starting with a octagon bbl., wouldn't you only need to remove the extra length of the mag tube, spring and drill a blind hole in the bottom of the barrel where the forend cap will be? If it's a "button" mag, only that portion of the mag tube extends beyond the forend cap. Wouldn't the cross pin for the mag tube that normally goes thru the ring work equally well going thru the existing forend tenon?

IMO... to make it really snazzy, turn the last half of the barrel round. That'll also reduce the outboard weight and such.

[Pete44ru]

If you're starting with a octagon bbl., wouldn't you only need to remove the extra length of the mag tube, spring and drill a blind hole in the bottom of the barrel where the forend cap will be ?

If it's a "button" mag, only that portion of the mag tube extends beyond the forend cap.

Wouldn't the cross pin for the mag tube that normally goes thru the ring work equally well going thru the existing forend tenon?

Winchester evidently didn't think so (and I agree), as presumably recoil will dissolve that sort of connection soon enough.

The longer magazine tube lengths have at least two points of restraint, but with a short magazine, at least one of those goes away, halving the resistance to movement under recoil.


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[marlinman93]

The mag tubes on most lever guns were retained at the end by a dovetail with a tube hanger that went through the tube and had a screw to retain it. But some button mags had a slight bulge pressed into the tube to keep it from slipping through the forearm cap and retain it. The old Marlin Model 410 from the 1930's used this setup.
One could easily have someone put some tack welds on the outside of the tube behind the forearm cap that would hold the tube once the cap was installed. But you need to also address the empty dovetail at the muzzle that will be left after it's shortened. Brownells sells 3/8" dovetail blank stock in 10" or 12" lengths, and it's pretty cheap. I keep a stick in my gun room just for restoring barrels that have an extra dovetail in them. You just need to cut it slightly long, and carefully file it to match the octagon shape of the barrel. If it's not a tight enough fit I use a punch on the back of the filler to displace metal and tighten it in the dovetail.
This method has the advantage of not being permanent, and can be easily converted back to a full mag without damaging the gun's appearance.

[Pete44ru]

some button mags had a slight bulge pressed into the tube to keep it from slipping through the forearm cap and retain it.

One could easily have someone put some tack welds on the outside of the tube behind the forearm cap that would hold the tube once the cap was installed.

I wasn't aware of that bulge method, Val - and, the tack welds sounds like a good (but hidden) solution.

Thanks !


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[marlinman93]

I wasn't aware of that bulge method, Val - and, the tack welds sounds like a good (but hidden) solution.

Thanks !


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I think a guy might also bend a ring of small diameter iron wire and solder it to the tube to do the same thing, if he didn't have a Tig welder.