CBI Krag Barrel and Project Rifle

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  • Doco Overboard

    Ultimate Member
    Couple of shots of a new CBI Krag rifle barrel. As always looks like a decent product and measures out well enough for pre- install inspection. Sight threads appear to be 8/32 and will work with existing screws for the 1901 ladder sight but I wouldn't get all nuts over tightening them until correct replacements are sourced or made.
    Crown and FS dovetail well done with good workmanship and chamber is smooth to a well defined throat to about 1/2 the depth of the lands. Extractor slot is a little wide to expose a little more case head but I suspect it will be just fine for modest patched bullet loads. That could actually come in handy later on.
    One thing that is different is that the chamber was advertised as needing finished reamed but you can see that a factory cartridge is seated to complete depth. Another is that there is an annular rim like on a Yugo Mauser barrel that is absent on the original barrels that I have. Not worried about it though because it will be easy to adjust if necessary. It's about .010 high. Rim thickness should be about .545. When the old barrel is off I can measure to the inner collar and then the bolt face to get a HS measurement just like a Mauser.
    A Krag bolt will also advance about .150 to overcome the force of the cocking spring and force the rim to the chamber mouth to make the cartridge straight and seal up the rim tightly or for dirty or gritty ammo. Thats an important point to remember if the decision is made to lap the single lug so the bolt handle acts as an additional safety or second lug. Now you can have crooked cartridge to chamber syndrome but that's another topic. It'll sting go bang though.
    Theirs some barrel specs and an impromptu way to form a wrench to get the job done in a pinch
    One other thing is the exterior finish is polished an even and the stub is done so the barrel will work in a 94-96 action without extra lathe work. This will be installed on #175536 a parade rifle that has been around the block a time or to so there are many other tasks to complete until finished.
    I can throw pictures and describe how repairs were made to the stock and give some resto tips for anyone interested in tackling repairs of that sort. If this has not already bored the hell out of someone already.
     

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    Doco Overboard

    Ultimate Member
    A few shots of the wood repair portion of the project.
    The fore-arm was cleanly cracked by some sadist on the starboard side and the recoil lug mortise had the typical hairline Krag cracks from the action screws not being adjusted properly.
    Actually, I suspect the rifle had been left for some time in an unregulated climate and had at some point been put away wet. The wood seems to be the lighter colored blonde or Italian walnut variety.
    I like this stock though because it's never been sanded.
    The trick to repairing cracks is to have a variety of clamping devices and in the case of this forearm, doing a trial run with your clamping, and then making sure the wood has been adjusted properly to provide a few pounds of pressure at the tip. Plus, the crack needs to lay straight just like it was. So now is the time to experiment with different clamping methods and the tools that work best. I use C clamps, different shaped blocks of wood that have been milled or even sometimes chiseled to fit different contours, surgical tubing, rubber bicycle inner tubes cut to fit anything that will not fail when the work is underway.
    This crack is radial and can be accessed from the barrel channel so material can be applied to both sides.
    There is also an age crack at the tang that needs to be dealt with and this is where a mistake was made, when blending comes into play.
    Clean or irrigate the damaged area with a solvent (acetone, I use a hobby needle dropper like for building balsa airplanes) then select a professional product that will work right the first time. First I was going to go with thinned acra-glass but knowing if the repair doesn't go right (some acra products are not a 50/50 mix like the gel) and temperature and working time could pose a problem ( higher temps = reduced working time) I used the gel.
    Key point here is to make sure the work is clamped together before adding threaded pins, or dowels ( the smallest brass rod stock threaded with a die yourself) For deep repairs a suitable size hole can be pre-drilled to prevent cracking, just make sure you do not over drill and reduce the capacity of the rod. Sometimes, a point can be ground on the rod and if its of a larger diameter, file a screw slot in it to turn it in or out if your 18v Dewalt is not up to the task. (chucks can slip and that makes thing go bad real quick even if you turn it in by hand on a DP)
    Prepare rigging, clamp, drill holes have everything laid out and then mix acra to the letter. Once this stuff sets up and proper preparation has been done its more or less permanent unless you grind it out.
    Use scotch tape where you expect run off and tape well so its tight. Once the excess squeezes out, scrape it off with a new razor. DO NOT PUSH ACRA INTO THE GRAIN, it will pop right off when your done.
    So, coat brass with acra, push some into holes but not enough to vapor lock it and run them in. I used to through the action mortise straight down nearly through the bottom. (careful measure here one shot only for good)
    Dr-awed up tighter than a you know what and then remove clamps and clip off with diagonals.
    Drill two more transverse holes to intersect the pins and insert 1/8" wood dowels that have annular grooves cut into them from the recoil lug area and tap in with a 4 oz. hammer. This is where you want gel packed into the 1/8" hole that when the dowel is inserted it starts to be pushed out. Clip with dykes and mushroom with hammer and get rigging out of the way.
    Then its just a simple matter of packing sufficient material into the fore-arm clamping appropriate with some clamps and long straight blocks 3/4x8", make sure gel has completely penetrated the repair area and let it rest for about 24 hrs in a warm area. IMG_0379.JPG

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    Doco Overboard

    Ultimate Member
    Ok, so once all that's done here is where you can make or break a nearly invisible repair and where I screwed up at the tang. When I dyed the acra, I mixed to light to match well.
    But there is a secret fix or maybe not, I don't know but here it is........ When you apply stain, use a dark walnut that has black crayola crayon melted in with it for where the repairs are made. Check out the Finn stock on the how many milsurps I did this year thread and decide for yourself. Easy and simple as taking candy from a baby or somebodies money on a "collector" stock. But now the secret is out and we all know how to examine things better.
    The other thing is, scrape stocks with glass, razor blades, spoon shaped hacksaw blades turned into scrapers to refine the area and leave the sandpaper to something that deserves the need. It compresses the wood fibers instead of ruffling them up or creating dips or waves, just drag that sucker out like screeting concrete.
    Use Chisels to trim dowels and a file and round or flat stone to smooth out pins. You can also drill deeper trim below flush and fill hole with like material fine sawdust mixed with varnish or an acra product. Exposed pins can be blackened with brass black from the advanced model shop or hobby store.

    Once this things all muddied up with resin from your shooting glove, dirt oil and grease it will be hard to see at the tang and up front hopefully because Ill have so much of that sweaty palm dirt pushed into the stock oil it will look for real.
    Form a Dutchman or small splice inlet into the tang in a bow tie shape from the inside then glass it in to keep it from continuing.
    Next Im going to do some metal work. Solder front sight post in, swap barrel and maybe get into some home nickle stripping from Caswell's products or Brownell's room temperature stripper.
    According to instructions from the distributors the warmer the outside temps the better the results. Or maybe Ill just put it all together for a shooter with a glued up stock and leave it like it is.
    Librandi's in PA will strip it if I send them the parts. Maybe Ill find an un-drilled sporter for parts I don't know, probably would be cheaper but this is not a cost effective project.
    Front Site post looks like it could almost be fit in the dovetail provided.
    IMG_0433.JPG
     

    Doco Overboard

    Ultimate Member
    I don't know yet? The dovetail is well done but thin, the site base has extra material but can be manipulated easy enough to do a good job. Hi force 44 would do it because one way or another the parts need to be fit.
    The easiest way would be to enlarge the dovetail with a dovetail file ground safe on one side, then dimple the barrel and site base in a drill press and bond with some kick ass epoxy.
    That could go bad though I guess, getting it snagged on something like a gun case or tree limb.
    The other thing is, the FSB is the replaceable part vs. the barrel. I cant think of the term, not expendable but serviceable replacement?
    Im open for suggestions, probably wind up 44ing it in case something else doesn't go well and the list of what could have been done better is a little shorter.
    It's just a bubba rifle, but its right to do the best you can all the time. I'm only a temporary caretaker, someone else may wind up with it one day.
     

    Doco Overboard

    Ultimate Member
    Finally got around to forming an action wrench. Wrench made similar to drawing with a twist. 1.310 ID, lug made from scrap fitted and then welded to a milled slot on the face of the wrench. Little welding and some grinding added a handle and presto, turned the action right off without damaging the loading gate pivot.

    Bad news is the barrel appears to have a chamber cut to full depth, is about 15 degrees from the extractor slot lining up and is going to need the breech faced and the chamber reamed to HS. Or... might be able to get it out of the single bolt lug or bolt face but on a Krag the bolt guide interacts with the receiver bridge and kind of acts as a safety lug so that could be tricky. Have to do some more figuring or try a different bolt maybe and see what happens but its still going to need finished chambered. IMG_0471[2704].JPG

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    53848714619__875D97B5-54AA-439E-A19B-BD74CCDCD0A0.JPG[2698].jpeg

    Anyway, some pictures of the home-made action wrench. Worked like a charm and was to easy so I should have known there would be more to do. You can see in the last pic the loading gate lug on the right of the wrench lug when it was being fit. Im thinking a factory wrench fit around the entire outside of the reciever somehow but Ive never seen an image of one.
     

    Doco Overboard

    Ultimate Member
    Contacted Mike at CBI. Great guy, responded to some tech questions right away. Never did say why the ring is evident at the chamber mouth but maybe he was busy or uncertain. He informed me that barrel should be .010 short. You can see that a cartridge seats right to the rim from one of the earlier pictures.
    Ill have to contact CMP which is where I sourced the barrel from and see what advice they may have. I think they may have received a return that somebody finish reamed and they resourced it unknowingly. Or maybe CBI possibly reamed it too long. Or that ring is the problem but that's not very well the chamber. Problem is because the Krag barrel is seated against the internal ring and not the face of the reciever I cannot check the clearance with a feeler gauge to determine approximate HS.
    This will be interesting. Glad I didn't screw it right together or fit the front site beforehand. This is the time to find out whats wrong, by inspection prior to installation. That little rim is, you guessed it .010.
    I have to figure out the correct way to go and get some more info before performing a costly irrecoverable act.
    Still some nickle/chrome stripping that needs done in the interim.
     
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    Doco Overboard

    Ultimate Member
    The ring is for adjusting HS! Little bit of a misnomer for advertised as chamber .010 short will require finish reaming but problem solved no biggie.
    Right on the CBI website! Thats what you get for not reading the instructions:innocent0
    Need to get some stripping done.

    3040SAAMI.gif
     

    Doco Overboard

    Ultimate Member
    So, finish reamed the chamber so it just closes on a .064 gauge and does not with a .004 sim stock added to it. Now the tricky part. In order to get the barrel to breech up and clock on index there was no way you can work with the .010 ring CBI manufactured the barrel with. Important point is to remember if you have a bolt with an altered face, excessively lapped lugs or a stretched off tolerance receiver you can still be in business by utilizing the extra material that is there.
    What I did was get rid of all of it because the only alteration to my donor parts is that it was once a parade rifle and looks like crap. So this is what I found out and how I did it.
    After careful trial fitting and observation I determined my parts were suitable. ( I have another rifle that was used as a standard and comparison) measured the depth of the shrouded bolt face on the US Krag. Swapped bolts and gauges between the parade receiver and other rifles (old barrel too for observing gauge fit and cartridge HS) to determine bolts would be of a suitable length and could be swapped between rifles when done.

    Real important note here, what I found was that the chamber on the new barrel was tight compared to cartridge fit. Whats important is the 30/40 is a tapered cartridge so just dropping in a stripped case and reaming away is not an option. You can do it I guess but I want to go easy on brass and have the bolt close and contact the shoulder and rim as close as I can get it. Plus comparison to the old barrel is that the shoulder is substantially longer and the diameter of the chamber was generous. My ammo and reamer is to Saami spec. No such thing in 1898 and this a turn bolt combat rifle that even with a helical cut on the bolt lugs to help lockup with a thick or mud caked rim there needs to be enough clearance to allow the cartridge to be easily extracted. Think Krag extractor and how it works, not the strongest. And different rim specs as well between manufacturers.
    I completely removed the ring at the chamber mouth. Then I installed the barrel to hand tight about 3/16" of an inch from tdc and checked how close the bolt was from closing on an unfired and stripped cartridge.
    Clamp the dismounted barrel into a vise and begin reaming. Whats happening here is that the body of the reamer is removing material from the chamber in the case area and where it tapers. The rim cutting portion is no where near the mouth of the chamber. Turn by hand and remove the reamer, detail clean both chamber and reamer, hand fit the receiver hand tight and check fit to the stripped unfired cartridge.

    WHEN THE RIM CUTTING PORTION OF THE REAMER APPROACHES THE CHAMBER MOUTH STOP APPROXIMATE TO THE DEPTH OF THE RING (.010) AND CHECK FIT WITH A CARTRIDGE NOT THE GAUGE.
    A 30/40 head space gauge can be used to check bolt fit because its a rimmed cartridge but it will not tell you when to stop in relation to the shoulder. At the exact moment the bolt will close on the stripped cartridge with the barrel hand tight your done. The reason is I increased the radial dimension of the chamber and just kissed the shoulder area.
    Then breech up to index, detail clean barrel and chamber, install bolt components trigger and mount barreled action into stock with the middle band top band and tension-ed trigger bow and bolts.( just slide them on and don't worry about the rest of the receiver components) Check that the bolt will close on your go gauge. .064 add a piece of .004 beer can, then make sure bolt will not close. Dont panic HS max is .071 on the Saami drawing.
    Get your PPE Welding gloves, protective clothing and eye-wear and some live ammo.
    Fire the rifle, what you should get is a nice centered primer strike and a shoulder that only moves forward .001-.003. and a body that measures just enough to let the spent brass fall from the chamber on their own without being larger than .459
    CBI has offered a barrel that will allow the end user to breech up a rifle that has some deficiencies, and that doesn't have a chamber that will swallow a reamer or create difficulties by over working the brass. You just have to make sure you do not make any assumptions when finishing the chamber by moving the shoulder to far forward. It would be just like the old one, alot of brass flowing forward.
    The only bad news is that the profile of the new barrel is a little more robust than the old one but its nothing a barrel bedding tool and some candle black cant fix.
    The other thing is I had to remove the barrel so I can try out some room temperature nickle stripper.
     

    Doco Overboard

    Ultimate Member
    So I mixed up room temp nickle stripper, immersed parts in a clean plastic bucket and hid it in the spare room. This project rifle is chrome plated but has been around long enough to have the chrome finish damaged from light rust exposing the nickle/copper underneath so fingers crossed.
    Hopefully the stripper will react enough with the poorly done nickle exposed areas and damaged areas to migrate underneath the remaining chrome.
    Maybe it will leave the copper, chrome or do nothing at all. But it's doing something I can see a chemical reaction occurring.
    The solution is three parts distilled water, to one part ethylenediamine and one part sodium hydroxide nitrobenzoic acid. It works faster in higher temps and removes the offending material at a rate of a 1/4 to 3/8"s a mill a hour.
    The other thing I did was degrease and then boil the parts in water and washing soda to remove any oils.

    The old girl just asked, whats in that bucket? uh o
    https://www.youtube.com/watch?v=jP-Rr-qscBU
     

    Doco Overboard

    Ultimate Member
    Done deal except for some small spots, now all I need is 77 oz of sweets 7.62 One thing I noticed is that the chrome would not come off the trigger very easy, maybe because its hardened all the way through. You can see where rust/oxidation has gotten under the copper at some point and removed it from the base steel. When the chrome comes off it turns into a black film just like when you do reverse electrolysis.
    Use gloves and a small wire brush to help it off around corners and stubborn areas. A couple of swipes will do it, safety glasses and goggles too.

    Now Ill dump whats left into a 1 1/2" pvc pipe and immerse the old barrel and try and get the chrome off that. I has a deep pit in the bore 4" from the muzzle but would make a good carbine barrel because the rest of it is sound. If I can get through that copper I should be able to get a decent finish without glass beading or peppering the hell out of it. IMG_0477.JPG
     

    Doco Overboard

    Ultimate Member
    IMG_0479 (2).JPG Doing some bedding before everything starts to come together. Here you can see where some candle black has been transferred to the barrel channel. The new barrel has a slightly more robust diameter requiring the chamber reinforce area to be slightly relieved.
    Wood is gently removed using a barrel bedding tool and razor blades used as scrapers. Periodically, the barrel is hand tightened to the receiver to make sure full contact is taking place. Going easy here, I want the muzzle end of the barrel to lay right on the nose of the stock with no upward or downward pressure and the tang exactly parallel to the large stock mortise for the action bedding surface.


    IMG_0480 (2).JPG Next, I laid out some tools for fitting the front site. Going from large to small here is the key. The new FS base is a couple thousands long so the length needs reduced. Working very s l o w l y here is important. To sloppy and you get a crooked site and a hell of a time soldering it fast. The tighter the fit the better.
    There is a slight dovetail to the FS milling. If you shorten the site base to quick you will lose the ability to match the bevel. So, what this means is that you match the angle of the dovetail as the base is shortened and then carefully reducing the length so that the base doesn't get short too quick. Don’t shorten and then file for the angle or it will be poorly fit and need to be filled with solder = it’s a new barrel and it needs sweated on so we don't want to roast it.


    IMG_0484 (2).JPG So now I have to locate the front sight. Install the rear sight base and pull a line through the hole in the peep slide. (Make sure the wind gauge is centered!) and then locate through the slot for the front sight. Make a mark that you can return to because the base and barrel dovetail is going to need tinned. Ill probably use a fine tipped sharpie. Inserted in the bore is a brass pilot to just under bore diameter that will be used for the calibrated eyeball. Double check your rigging for plumb and your in business.

    IMG_0483 (2).JPG The tools used for tinning the base and the barrel. De-grease your parts and make sure they are bright. Once everything is lined up, cramp your front sight base to the barrel and heat until a bright line appears. Feed you fluxed wire solder into the joint and it will be attached. Use the number 2 lead pencil to protect everything you don't want covered with solder clean. This repo front site base is pretty elegant with sharp corners and radius all the way around. Ill probably de-horn and blend it in to make it look more like a good facsimile of an original before bluing/browning with Mark Lee express metal finish.

    IMG_0485 (2).JPG
     

    K-43

    West of Morning Side
    Oct 20, 2010
    1,881
    PG
    That's really nice work. I'd be afraid to try to remove the plating myself.
     

    Doco Overboard

    Ultimate Member
    View attachment 226051 Decided to go with Mark Lee express blue. It was a toss up between the blue and brown product selection. Instructions indicated the brown would turn black when immersed in boiling water so I stuck with blue.
    What I liked about the product was its ease of use, high coverage and of course final finish.
    All the small parts including the action were finished on the kitchen stove. Boil the parts in washing soda to degrease, immersed in distilled water (I just used bottled water) to heat them up. Once removed from the boiled water the parts will quickly dry and then swab on the blue. Use a disposible sponge on a stick like for painting and some Q-tips for the hard to reach spots. It will quickly dry and leave a yellow haze when the metal is etched and penetrate the pores of the steel quickly. Card lightly with a degreased stainless brush, dip back in clean water boil to raise temperature then re-coat. Once all your parts are done, boil for a few minutes to seal the deal where they will turn to a velvety blue (black). The resulting finish will then be carded and buffed to the luster you desire.
    Its important to note here that a valuable lesson was learned here. When I stripped the chrome/nickle I was left with the copper wash that was part of the plating finish. So what I had to do (not really but I did) was take a chance and use an aggressive approach to getting that mess out of the way.
    After all the scrubbing and stripping was underway and for the purpose of moving the project along I just bead blasted the parts. The result was nearly perfectly cleaned parts but gritty as hell. Now keep in mind this was a save project. I doubt there is any SRS numbers affiliating this rifle with a charge up San Juan hill. What I found out was that I should have stoned out the minor pits in the magazine box and small areas of the receiver for a stunning final finish. A combination of glass and black oxide grit stripped off the copper, any remaining chrome and a hundred years of dirt. Should have just went right to it and eliminated the room temp strip. The reason is that the copper would have just peeled right off with the chrome. A little extra time in the bead blast cabinet but when it was done, it was smooth as a baby's ass.

    View attachment 226052 This is how I did the barrel. Grease the bore and fill with boiling water. (this keeps the plugs from blowing out due to the pressure difference when its dunked) Plug the barrel and the chamber with some dowels and let it eat. My high force solder line didn't take the blue but it didn't melt out either after being contacted by the solution. Some solder black will take care of that later on if I cant stand being off one wingauge point or something and I get bored.

    View attachment 226053 Slightly out of focus finish close up.

    View attachment 226054 Getting close and all slathered up with BLO. Metal parts and everything. Thats right, get that stuff right into the metal so that with some handling it looks like its been hot oil blackened, but I don't think that's going to happen very easily because the Mark Lee is a decent product, works as advertised following simple instructions and is extremely durable.
    I did however protect the receiver ring and barrel when I final clocked the assembly. I may polish the bolt back into the white after I shoot it in, then I'll be able to see what I'm doing as it turns brite or just find another bolt one day, probably easier.
    I need to make a front site blade out of a copper penny and then regulate the sites.
    Nowhere near as pretty as an original in good shape with a high percentage of original finish, they are works of art in my opinion, but a good representation of what can be done in the home garage for enjoyment or casual shooting.
    This was not a cost effective project because of the time and the investment for the new barrel and chemicals but this rifle should be good for another hundred years or so. Plus it may shoot worth a damn too.
     

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