336 Marlin Question (hole in chamber)

[randyrat]

I picked up a nice old 336 very low price. Everything on it is in nice shape and it shoots cast bullets almost or on the edge of my shooting ability at 100 yds or beyond. It's a 1949 with ballard rifling. Now i noticed some "want A be" gunsmith drilled 2 extra holes for a scope mount. 1st hole - through the barrel/receiver into the chamber maybe 1/2" from the web of the brass and another in the cutout/ thinnest portion of the receiver( this one dosen't worrie me)... I've shot lots of cast through this gun but never full nuke loads. Is there anything i can do with this gun to restore it or should i keep it as a shooter.. There is no evidence looking at the empty brass. I just wonder is this a gun worth it or should i try to fix up or just leave it and shoot it.

[Scrounger]

I take it you have been using it with no problems; I think I would continue to do so. If a case lets go, it can vent through the open hole and is not likely to harm you. If it really bothers you, have a new barrel put on and plug the screw hole.

[creekwalker]

I’d either have the barrel pulled or have a very good welder fill the hole or re-barrel it. Whichever one of these that’s done will most likely require the chamber to be cleaned up a little so that’s not a problem.

Creekwalker

[S.R.Custom]

The hole in the barrel is a weakness, and a potential source of cracking (and subsequent catastrophic failure). Pull the barrel and have it TIG welded. As for the receiver, just put those little filler screws in the receiver holes and call it good. Any more than that, and you'll have more money in the gun than it's worth.

[crossfireoops]

I do a LOT of TIG work, and all the other varities of welding.........I'm not real sure that I'd recomend welding that one......but can give you the procedure that I WOULD use, if I had to.

I would be more inclined to pull the barrel, tap that hole to the closest 40 or 48 pitch as I could, and that turn in screw, and index it longitudinally. Would then pull the screw and carefully hand file / stone in chamber radius,......with everything dead clean / de-greased, .....would set the screw into index with Loctite RED ( NEVER underestimate the power of Loctite red ) . Once the Loctite's cured.....would judiciously hand dress any asperities, and cut off the cut off the projecting portion, ....than hand file to conform to Shank threads......... I think you'd be good to go, from there.

The weld procedure's a mite more complex, and would demand good skill level.

GTC

[randyrat]

I have a screw in that hole now and it dosen't leave much air gap under it. Maybe thats why i haven't seen anything wrong with the shot brass. I have to think about what to do with it....Thanks for all the replies...Gives me more options.

[leftiye]

4140, and other barrel metals don't like welding/welders - very hard to do correctly, changes the metallurgy of the metal, and causes stresses. I like crossfire's approach, put a screw in that hole. If you can drill and tap it so as you can just barely get the screw in (very tight fit, undersized tap or oversized screw) ,and then file the screw off, and re touch the inside with a reamer (got to have jest a little itty bit of screw into the chamber), then it will be pretty strong. 30-30 shouldn't be much more than magnum (actually some less) pressures. Use a grade 8 screw. As it sits now, your brass is all that's holding the pressure.

P. O. Ackley is supposed to have unscrewed the barrels on 94 Wins. and used extended firing pins to fire cases seated in barrels 1/4 " or more from the bolt face. The cases alone held all but the highest 30 -30 loadings via grip on the chamber walls. This is slightly different than the present situation, but I'd guess that the brass plus a tight plug screw should hold up if you don't go too hot.

[KCSO]

As a matter of fact I had a discussion with another gunsmith about chamber holes. As an experiment to test our theory we drilled a hole into the center of the chamber of an 8 mm Mauser (6x40) tapped it and put a screw in to fill the hole. The gun stood everything we could load in it including German surplus ammo. Although it may not be the best solution I think Super Mag had this one dead on. A screw will do the trick just fine for 30-30 pressures.

[MtGun44]

As I understand it, you have a nearly flush screw filling the hole.
Seems like the issue is pushing brass into the hole and making
it difficult to extract.

I'd clean up your screw real well and put a dab of J-B Weld (filled
epoxy) in the hole, building it up slightly too high. When it has cured
chuck up a strip of wet or dry about 360 grit in a split dowel and
polish the J-B Weld down until flush. The chamber will just be
polished slightly, the J-B is way softer and will cut pretty quickly.

The J-B will be trapped, so should be strong enough to keep
from building bump on the brass that could affect extraction. The fully
trapped J-B should stand up to full pressure with no problems, and the
threads should help keep it in place. Don't scrub the bore with
brass or ss brushes, only plastic and avoid harsh chemicals as much
as you can and it will probably shoot full power .30-30s for as long
as you want with no bad effects. If the little filler comes out, do the J-B weld
again and go for another few years.


Bill

[crossfireoops]

Most Epoxies will rate somewheres around 18k psi "Compression"......were I to got the epoxy route, .....Devcon "Titanium putty" would be my call......but the stuff's avail only in 1 LB. kits, and Has to be worked DURING cure cycle, you get about 1/2 hour, in cool conditions............We built up some worn pump shaft bearings with the stuff once..........Pumps happily till in service.

Some careful bench work with magnification, and a round ceramic stone sould allow one to have the screw itself support the case. at only .500" into the chamber, there should be a fair bit of room.

Final cherrying out / blending.......with round arbor and fine crocus / wet emory could well see that feature become almost invisible.

I would NOT try to clean off a grade 8 screw appurtnance with a reamer........not as well as what that rifles running..........equal chance 'tween chipping a flute, ....or bodging chamber.

Leftiye, thank's for re-inforcing my spooked at welding HP Chro-Mo........not saying I can't, more like wouldn't.

Randyrat, I'm all set up to do the Screw repair, If you get the barrel spooled off, and would like to send it over,......will do. Shore and clamp that reciever, prior to twisting.....they are EASY to distort.

Best of luck, and Merry Christmas.

GTC

[BruceB]

The talk here about skilled welding reminds me of a saying I heard at the mine, about what defines a "good" welder:

"A GOOD welder can weld a banana peel to a 2x4...."

[Junior1942]

A local welder told me he could take his TIG welder and carve his initials in a beer can.

[mtgrs737]

Wouldn't weld it without re-heat treating the barrel. I would just find a used or new barrel and replace it. Or just keep shooting it as is.

[MT Gianni]

"Pass any test they through at me in a sandstorm in Casper coming off a 3 day binge" is my favorite. Gianni

[ebner glocken]

Yes, it can be welded. I do have access to a shop that can do it and if it were mine I woudn't see the need in it for 30-30 pressures. Not worth the time much less the money if I had to pay someone to do it.

[ammohead]

The old welder at work says he can weld everything except " a broken heart, or the crack of dawn".

ammohead

[crossfireoops]

Welder Haiku.....

I have holes in my shirt

My hat's on backwards

Would someone tell me what's going on

GTC

[JIMinPHX]

4140 & most other rifle barrel materials, except those used on some rimfires, will TIG-weld well, but the heat treat will be gone & that is a much bigger problem than a small tapped hole in the chamber. Rimfire barrels are sometimes made out of a free-machining alloy that is colloquially known as lead-loy. That stuff does not weld properly by any process that I know of. It just sort of melts away from the bead as you lay it. Porosity of the weld is quite bad too.

[Sam]

Jim,
those 22 barrels are made from "screw stock" which is a very low alloy carbon steel. You can weld it nice, just need the right filler, clean(remove the paint/laquer) coat hanger wire.

Personally I won't weld barrels. They just aren't that expensive, why risk it.

Sam

[JIMinPHX]

Sam, I think that we may be talking about two different barrels here. Coat hangers were the only welding rods that I owned when a mixed gas torch was all I had to weld with many years ago. I then moved up to soft bailing wire for a really nice smooth bead without the little bit of sparkle that the coat hangers can sometimes give you when welding. I am pretty familiar with that method of melting steel together, but some of the rimfire barrels that I have seen did not want to play ball with me. Some of them just run away under the bead when you put the heat to them. they also produce very short & shiny chips that don't have any sharp edges when turned too. I could swear that stuff was in the 12L14 family from the way that it handled. Not all of the rimfire barrels are that way, just some of the ones that I ran into. Just trying to tack weld a loose dovetail for a front sight gave me a case of the gloops on one of them. That’s how I ended up finding out how the stuff turned. I needed to recut the crown. I then ended up with a press fit sleeve for the front sight.

[tn gun runner]

put JB or marine-tex in hole, put set screw in top of gun, let the JB harden and polish chamber . did one 30 yrs ago and my friend shot it for 10yrs and sold it and still was in tack

[crossfireoops]

put JB or marine-tex in hole, put set screw in top of gun, let the JB harden and polish chamber . did one 30 yrs ago and my friend shot it for 10yrs and sold it and still was in tack

I'm inclined to agree,....we're making far to big a deal outta' this small, and easily acomplished repair.....that can be done quite safely........without welding.

on;y thing I would ask.....use an EXTREMELY soft screw, ...if goin' through both reciever and barrel assembled. That's a fine rifle, and somewhen, Lord Willin' someone will want to dismantle / re-furbish it.......

While it's shooting as well as it is....FIX it, and keep shootin' it.:Fire:

Best Regards,

GTC

[uscra112]

Piper Cubs, and just about every other tube-framed airplane of the pre-WW2 era were welded chrome-moly tubing. But welding a heat treated barrel? I dunno. It'd likely warp it, at the very least.

I agree that putting a screw in snug with a strong grade of Loctite will do the trick, unless you're planning to shoot 60K PSI loads.

[Lloyd Smale]

custom gun makers weld on guns all the time. i think if hamilton bowen can cut the top strap off a 44 mag and weld a new one it place and have it hold a small screw hole would be very easy. Dave clements welded two holes in one of my old models that some idot had a scope on and you cant even tell it was done. I welded for a living for 10 years and have a little knowlege on the subject and surely wouldnt have had him do it if i thought it would have been dangerous.

[randyrat]

I just talked to a very good gun smith,known for miles around,does very good/GREAT work. He said he will not weld it, because the hole goes all the way through. Of course, he also said it was unsafe to shoot. Any gunsmith in business is going to tell you that for litigation sense. This "Smith" told me he could re-barrel it,but he could weld the extra hole in the receiver. I figure on going the screw route for now and do the best job i can do on that. Then some day i may rebarrel it. Would i be able to find another barrel to match?.... New or used ?? Is there different thread pitches on Marlins? Do they all time up/head space good? From year to year? Anybody have a good barrel for a marlin 30-30 (1949) ballard rifling? Or will i have to go with a new barrel and make it a (1949.......2008) Marlin 336 Man i got a lot of questions... Thanks for replys to date.

[crossfireoops]

custom gun makers weld on guns all the time. i think if hamilton bowen can cut the top strap off a 44 mag and weld a new one it place and have it hold a small screw hole would be very easy. Dave clements welded two holes in one of my old models that some idot had a scope on and you cant even tell it was done. I welded for a living for 10 years and have a little knowlege on the subject and surely wouldnt have had him do it if i thought it would have been dangerous.

All due respect, ...Ive been welding simce 1965, and have done a LOT of Chro-mo aircraft work, as well as Motorcycle, and race car frame work...........

The Inverter advanced square wave Heli-arc set up out in my "Welding coop" markets in the $10K + area, last I priced out that set up.

A revolver frame can be Re-Heat treated, after mods to nulify any included weld induced stress......

A Rifle barrel CAN'T....................unless you're going to send it to a Vacuum / inert gas induction furnace / heat treat outfit, and than re-blue, etc....and you'll run a good risk of screwing up the barrel' s accuracy.

I know exactly the weld procedure I'd use to make that repair virtually invisable,
That ain't saying I'd recomend it, ......'cuz I don't.

Chromium Carbide precipitation leads to EMBRITTLEMENT, in the absence of post weld heat treat / stress relieve.

GTC

[shunka]

For a replacement barrel you might try numrich
http://www.e-gunparts.com/DisplayAd.asp?chrProductSKU=454010&chrSuperSKU=&MC=

[John Taylor]

I weld on a lot of old barrels but in this case I would not use welding. All welds will shrink a small amount so a welded barrel will have a tight spot in the bore. Most of the barrel I weld will be getting a liner so that does not bother me. Nickel steel and 4140 barrel can get very hard if you cool them down to fast.
Plug the hole with a screw like some of the others have suggested. Do not try to take the end of the screw flush with a chamber reamer. It will break the reamer or force it to the opposite side of the chamber making the chamber oversized. A dremal tool or jewelers file would be the tool to use, with care not to touch the original chamber. The threaded area can be done with a small triangle file. The screw does not need to be hard. If the hole is for a scope mount it will probably be a 6X48. Scope mount screws are hard. Use red loctite to keep it from moving. I use red loctite for holding liners and it works great. All this work being done with the barrel out of the frame, a screw through the frame into the barrel will make some future gunsmith very upset.
Another cure would be to line the chamber. I do this on barrels that have a good bore and a pitted chamber.
A tig torch could be used to plug the holes in the frame but if this is just a shooter and has no collector value it would not be worth the trouble.

[Molly]

When I was a practicing gunsmith, I used to have the occasional drill-through brought to me for replacement, but there's a real simple fix that's essentially permanent.

First, sand out any burrs that are projecting into the chamber with a bit of 360 grit and a dowel. If the hole isn't threaded, go ahead and thread it for the nearest size plug screw. Degrease and dry EVERYTHING. Now thread a plug screw into it until you can just see it, or feel it with a bit of brass rod. Then back the plug screw off about half a turn, to be sure it isn't projecting into the chamber. Now use a second second plug screw to jam the first one so it can't move. If you need to, grind the second screw to make sure you can still mount the scope that was behind the problem in the first place.

Now take fired, resized case and add a square of scotch tape at the hole position, so the case has to be pressed into place with finger pressure. The idea here is to force the case tight up against the hole, and keep it there.

Now put a little paste wax on the case to make sure it doesn't get stuck in the chamber. Mix a few drops of 20-minute epoxy and use a toothpick to put a drop inside the chamber at the hole. Rotate the case so the release agent is against the hole, and press it into place. If you have room, put half a drop in the top to lock the jam screw in place too. Leave it alone while the epoxy cures.

Next day, eject the case, and use a bit of dowel to sand out any beads of the epoxy. Oil and you're done. I never had one of these come loose or cause any other problem. Don't worry about the compressive strength of the epoxy: under these conditions, even putty would serve, though not for very long. You only need something to keep the brass case from poping up into the hole. The strength of the barrel may be 'officially' compromised, but it's held up against some fairly potent rounds, including 308 and 22-250.

HTH

Molly

[Junior1942]

Molly, I think you should still be a practicing gunsmith.

[randyrat]

Thanks Molly for the detailed fix. Sounds like a Winner!