Rehabilitating a 200-year-old Jaeger Rifle: Conservation, Repair and Restoration

[BobSm]

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As a member of the Sons of the American Revolution, I regularly do living history presentations to schools and youth groups. As my ancestors during that war were Pennsylvania riflemen and gunmakers (Newhard, Kuntz and Moll), one of my classes is on the evolution of the long rifle from the original German Jaeger. Not owning a Jaeger, after a long search I purchased this percussion conversion in an internet auction as an inexpensive, rusted-out relic to pass around in class. Imagine my surprise to find this gem arrive in much better condition than I thought, so in addition to conservation efforts necessary for the piece will survive another 200 years, I’ve gone a step further to put it back into firing condition. I’ll detail all those steps, but first a before and after preview:

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The first phase is dismantling the rifle, which in an old, pinned muzzleloader is a delicate process, as wood dating to the days before central heating has since shrunk around the inletting, and a combination of age and environmental conditions has deteriorated the lignin – the natural glue that holds the wood fibers together. The consequence is that old wood is tight and perhaps rust-bonded to the metal, is brittle and splits and chips very easily. Further, every time storage temperature and humidity changes significantly, the metal sweats moisture into the inletting, and when combined with petroleum compounds used to prevent rust, often causes the fragile wood of the inletting unprotected by finish to become punky and soft:

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Often there are tradeoffs between getting the gun apart, which is necessary to conserve it, and causing some controlled damage, and I’ll show some techniques to minimize problems. First, I use Kroil penetrating oil liberally around the edges of all the inletted metal parts as well all pins, screws and bolts and allow them to soak overnight. I find this product to be among the best in its ability to break rust bonds between metal and metal and also metal and wood. I’ll clean it out of the inletting later.

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Screw slots are cleaned of loose rust and debris using penetrating oil and dental picks, driver bits are fitted carefully, altering them on the grinder if necessary, and tapped with a hammer before applying torque. A light to moderate tap with the hammer often breaks the rust bond, preventing a damaged screw. Driving out rusted pins requires supporting the surrounding wood using padded clamps to prevent a bent or rusted pin from catching on the far side of its hole and splitting the wood.

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Once I get into these old guns, I rarely regret dismantling them completely, as the amount of active rust here makes it clear this rifle wouldn’t survive another 200 years without proper attention.

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Also interesting is attempting to date this rifle. The lock and drum are from circa 1850, but the screws were all hand-made using a screw plate, and date from well before 1840. The swamped barrel is extremely soft iron, and also is an earlier example. Yet I can’t find any evidence of the lock having once been a flintlock or being re-inletted into the stock. Nor can I find any information about the builder, whose largely illegible medallion shows a crown with the name IP (or JP) Roos-bach (or Roos-back) beneath. Further, it’s clear that the lock bolts have either been reused from the previous lock or were salvaged from another rifle, as they don’t fit the lock well. Hence I suspect a circa 1800 rifle needed restocking, and while they were at it converted it to percussion using a new lock with the original barrel, fasteners and furniture.


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The worst case in disassembly is when a previously bent or rusted pin drives out the lug with it, causing further damage to the inletting. If a pin won’t budge after soaking, don’t force it. Use a Dremel Tool with a cutoff wheel to cut two slots in the ramrod channel to cut the pin so as to free the stock from the lug. It’s better to repair the minor resulting wood damage than to risk shattering the stock. In a firearm built or repaired prior to around 1900, any parts that are glued to the stock like this horn nose cap remnant, or suspected of being glued-in were done using hot hide glue, and the glue bond is easily released using light heat and a chisel to pry it free. Later repairs done using modern glues also respond favorably to heat (or steam using a sopping wet rag applied to the joint and touching the rag with a soldering iron), but sometimes they have to be cut apart, rejointed and reglued.

Continued...

[BobSm]

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Before I stress the forestock by jointing it for the patch required at the muzzle, I repair the several minor cracks up and down the barrel inletting by coating the barrel with paste wax as a release agent, and cleaning and gluing the several old cracks using marine epoxy with the barrel mounted so I have something substantial to clamp to. The cracks are cleaned with trichloroethylene solvent and a toothbrush, are allowed to dry, followed by an application of walnut-dyed epoxy in two coats. The first coat is applied thin and allowed to soak in for 15 minutes, followed by a second coat thickened with a high-density filler like cabosil. I prefer West System, but others will work as well, including Acraglass. Paste wax works well as a release agent, and is easier to use than the alcohol-based commercial preparations. Wild tales about gluing actions to stocks and having to whittle them off are exactly that, because releasing epoxy-metal bonds is easy. Raising the temperature of the metal to 200 or so degrees using a soldering iron or torch easily releases the bond to metal, and with no ill effects to the epoxy. If this rifle were going into a museum, I’d use period hide glue. But in private hands, I can’t predict its future, and this thin forestock of brittle old walnut needs all the help it can get if this rifle is to be fired again regularly. In addition to high strength and not requiring clamping pressure, epoxy also glues to its old residue similarly to hide glue. So if these repairs ever crack again, they can be reglued without further damage. In turn, never, ever use polyvinyl acetate glues like Titebond on a valuable antique, as they can’t be successfully reglued or even reversed. While the glue is curing, I perform minor tasks like cleaning the old tallow out of the patchbox.

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Next I measure and cut the patch for the muzzle (here you can see my previous epoxy repairs in the old cracks). Saving period wood scraps salvaged from previous antique repairs is useful, but the most important factors when making a patch are accuracy in matching the grain and cutting the joint, and the easiest material to acquire for this purpose is a turning square intended for lathe work. A turning square of the same visual grain density provides a long length of two vertical and two flat-grain faces to find a section of grain that best matches your needs, and you can always age and dye the final, sanded surface later to get the color right. As they are relatively inexpensive, you can purchase several from different vendors to have a better selection of natural colors and grains. Here I’ve selected the section of a turning square that best matches the forestock, and have turned it down on the lathe and bored it using a Forstner bit to save time over gluing on a larger hunk of wood and having to whittle off everything that doesn’t look like the forestock. As the gluing surface is small and the old wood relatively fragile, this is the best approach for this rifle.

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Here I’ve jointed the broken surface to dead straight and flat using a block plane, and am carefully fitting my vertical-grain patch to align it with the grain of the forestock.

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Enough can’t be said about grain alignment in regards to both strength and cosmetics. The stock on this Jaeger was expertly cut from a tree crotch – when the forestock is aligned with the strips of my laminated benchtop, you can see the bend of the buttstock’s grain at the wrist, aligning the grain (and strength) of the wood perfectly to the moment of effort and stress of the stock. This also prevents the cracked toes so commonly seen on full-length rifle stocks. When making a full-length stock from scratch, if you can’t find a blank cut from a proper crotch, you can achieve the same results by rough-shaping the wrist and heat-bending the stock. I have a detailed article on how to do this on Wiktor Kuc’s “WK Fine Tools.com” website. After glueup, the first step in fitting the rough patch is inletting the barrel, which isn’t straightforward with a heavily-swamped barrel. Hence I’m using an alcohol lamp burning mineral spirits to apply soot to the barrel to mark the high spots for paring, a slow but accurate process.

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Final shaping is accomplished using coarse and fine rasps and even finer machinist files and scrapers before abrasive paper. At this stage I begin to keep a bowl of mineral spirits with a towel handy. When you want to see how the wood will look under a finish, a simple swipe with the dampened towel reveals surface flaws you won’t otherwise see.

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The new horn nose cap is mortised using several layers of masking tape as the saw index to cut the shoulder followed by rasps and scraper to shape the tenon. Before glueup, the horn stock was smoothed using a belt sander, boiled in water until it was heated all the way through, and bent around the mortise to set its shape. Cow horn is layered like your finger nails. While it bends and takes a set easily with heat, it doesn’t cut cleanly with woodworking tools; however it sands to shape very nicely and glues easily. To insure there would be no flaking in use, after bending I allowed it to dry and treated the edges with thin cyanoacrylate glue before assembly. I use epoxy glue to install the nose cap, as the tenon on the end of the forestock is fragile, and already has epoxy repairs. If this nose cap ever requires replacement, it will be a simple matter to carefully grind it off and fashion a new one. I installed the nose cap over-thick with rough-shaped edges, and finished it using a power sander after the glue cured. Last, I raised the grain a couple times on the entire patch assembly using a water-dampened towel during final sanding.

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After final sanding, to age the wood before dyeing, I apply bleach to age it. Normally this is done using a slurry of oxalic acid granules dissolved in mineral spirits, but here I’m using plain chlorine bleach, which imparts a slight yellow cast to the wood which matches this French Walnut better. After drying I remove the small amount of raised grain using 400-grit abrasive paper, and begin the process of diluting brown aniline dye with clear alcohol until I achieve the color that best matches the old wood, testing it on matching scraps as I go.

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Only after all mechanical repairs are complete do I clean the stock, the idea being to dissolve the top layers of dirty, degraded finish and spread them to the repairs to blend color. Solvents used for cleaning depend on the finish, so you have to test it. Alcohol dissolves shellac, acetone dissolves lacquer and methylene chloride dissolves hard varnishes, the goal being to remove only the degraded layers of finish, and not strip to bare wood, thus removing the fillers and age patina. For stocks still in their original finish without extensive repairs involving new wood, the proprietary restoration product Vulpex Soap Concentrate is often adequate, especially on oil and shellac-based finishes. This stock, however, has extensive repairs and has been recoated during its life. The hard varnish has taken an ugly, yellow cast and the fine, flat-top checkering is full of hardened finish as well caked-in dirt. After scrubbing the inletting thoroughly with trichloroethylene to remove any petroleum oils, I use the proprietary restoration solvent Formby’s Furniture Refinisher and #0000 steel wool and a stiff tooth brush. Forby’s is stronger than basic solvents like acetone, dissolves all finishes except polyurethane and epoxy, and I’m careful not to take off too much, too fast. Only in the checkering to I remove all the old finish.

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After neutralizing all the solvents by scrubbing with mineral spirits, I mix oil pigments with drier to match the stock color and feather a tiny bit of pigment atop each of the repair lines to cloud them. Then to set the color I apply a wash coat of Truoil wiping varnish thinned with mineral spirits and a few drops of cobalt or japan drier added. I apply it to all the stock’s inletting, too, as a sealer. The drier aids the new coating amalgamate with the residue of the old coating beneath, and is only necessary for the first coat. Using driers on subsequent coats can make the final finish brittle and prone to chipping and delamination. I prefer Truoil because it’s a natural oil-based finish that builds, rubs out nicely, and is reversible and renewable. It is a soft finish that wears off in use, but in turn, is also easily top coated, and can be rubbed down to bare wood to fill pores and voids. Never, ever use a finishing material that contains polyurethane or epoxy on an antique, as plastics are much more difficult to remove when the time comes for future repairs and restorations.

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On this stock I apply six or seven thin coats, rubbing each back to fill imperfections using #0000 steel wool. In the initial coats I apply a glaze to all repair lines and ragged holes that were filled with dyed epoxy to cloud the finish and hide the repair. Here Burnt Umber and Burnt Sienna provide the color match I’m looking for. The edges of the glazed areas are feathered and allowed to dry, then can be feathered again using #0000 steel wool dipped in mineral spirits. The final finish coat is applied relatively thick and allowed to cure for a week before rubbing out using #0000 steep wool lubricated with a high-end, hard carnauba wax. Renaissance Wax or Kiwi Neutral Shoe Polish are good choices.

Continued...

[BobSm]

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The last step is to carefully clean the hardened Truoil out of the checkering using Forby’s and a stiff brush, followed by a coat of linseed oil. The linseed will soak in and provide the classic matte contrast between freshly-cut checkering and smooth stock finish.

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On to the metal parts, although much of this is out of sequence because the wood-metal work was largely done in parallel. The decision to bring this rifle back to firing condition was based on zero erosion to the thickness of the breech parts on both the inside and outside. And note how the breech plug is sculpted to improve ignition speed and contrast the rounded, loose-fitting threads of the breech plug with the sharp, tight-fitting threads on the drum, more indications of pre-1840 and post-1840, the barrel assembly being much older than the percussion conversion. As many of these old guns were stored loaded, in effect pouring and storing a thimble full of salt down the barrel and leaving it for a century, absence of outside corrosion means nothing. I would not attempt to shoot an old muzzle loader without a thorough inspection of all breech and bore surfaces.

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To preserve the rifle, all the active rust has to be removed from the rust pitting and protective coatings applied and maintained to prevent future rust under normal storage conditions. I prefer to accomplish that with minimal disruption to the existing surface finish, but the two aims aren’t entirely compatible. As the bore is the most critical section to clean, I use a proprietary nitric acid rust remover bath and heat on the barrel, and a cold phosphoric acid bath on the remaining steel parts. The nitric acid solution is stronger and works faster, but leaves nothing in the pits to aid in preventing future rust. Hence once the barrel is removed from the acid bath, it must be stabilized immediately using oil or finish after a hot-water rinse.

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The phosphoric acid, however, when soaked overnight, allowed to dry and scrubbed off using hot water to remove the bulk of the sludge, leaves a coating of phosphate salts in the pits to deter further rust. So after the nitric acid bath, instead of drawfiling the pits out, I spot treat the barrel and bore pitting with phosphoric acid before finishing.

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I clean the bore using three grades of successive abrasive pastes (fine Clover followed by two grades of JB) on a succession of tighter bronze brushes wrapped in #0000 steel wool and patch-wrapped jags, using a rod with a centering cone so as not to abrade the soft barrel in all the wrong places.

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The cleaned bore (right) still shows some minor pitting, however the tool marks remaining on the top of the lands indicate this bore was never very smooth to begin with, and I elect to stop here. If I decide to incorporate this rifle into my live fire demonstrations, I’ll want to see how it groups before deciding whether to get more drastic with poured-lead laps and recutting the muzzle’s crown to optimize accuracy. So I touch up the nicks in the crown using fine needle and round files, and measure and record the twist of the rifling and diameter of the bore for selection of ball and patch sizes should the time come. The rifling twist is one turn in 27 inches, which matches the length of the barrel and another indicator that this is an early barrel. It wouldn’t be until the 1850’s that builders began to understand that patched round balls required much slower rates of twist for optimum performance. Until that became better understood, many traditional builders used one full turn in the length of the barrel.

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I use a combination of phosphate bluing (Brownells’ Oxpho Blue) and plum brown combined with rubbing out with #0000 steel wool to bring the surface colors to a uniform appearance of age. In these photos, the lock plate and hammer on the right are in their natural, cleaned state untouched by chemicals, with the remaining parts colored to match them. The front sling swivel shown is a new replacement. Where traditional rust or fire bluing doesn’t make sense, I like Oxpho Blue for jobs involving minor pitting. It’s easy to apply, it doesn’t after-rust, and it leaves a rust-protective phosphate coating more durable than other blues.

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To prevent the problem of frozen pins in the future, I replace all three steel barrel lugs with brass, staking them in place for security using a punch. Plus I replace all five pins assembling lugs and thimbles to the stock with new, hardened pins. As the severe damage to the muzzle end of the stock was caused by the front swivel lug failing, I deepen its dovetail as well as stake and soft-solder it in a belt-and-suspenders approach.

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At this stage I also center punch all the stock’s pin holes I repaired using either wood or epoxy so I can drill through the stock and new lugs together, installing the barrel in one, continuous operation.

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The pin holes are drilled using a hand drill where I have a good index or center punched, plumbed and drilled through-and-through with the barrel mounted using the drill press. Overlong pins are tapered on one end, blued on the driving end, driven through, trimmed, blued and driven flush.

Continued...

[BobSm]

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The result is a neat pin installation that includes epoxy-lined holes for the pins that experienced the most wear and tear in use. As their thread fit is so poor in the 8-32 holes of the percussion lock, I decide to replace the lock bolts. Here I have the original, undersize bolts and two pair of replacement candidates to find the set that fits the lockplate threads best. Not all storebought bolt threads are exactly the same. As the new bolts have thicker shafts, I measure and hand-ream the stock holes and trim the new bolts to length.

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All screw holes in the wood are coated with thin cyanoacrylate glue to strengthen the threads. This is especially important in screw holes drilled into end grain, a naturally weak construction. The screw beneath the breech plug that mounts the front of the wooden trigger guard was so deteriorated that I replaced it, to include filling the end-grain pilot hole in the fragile guard with dyed epoxy and redrilling it when I fitted the guard.

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Before I installed the barrel I mounted and aligned the sights using an optical boresight, and carefully refitted the patch box lid and spring, scraping off finish as required and waxing the lid for ease of use.

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The last step is mounting a replacement folding tang sight. This one is an American sight, and mounts slightly differently, but is of the correct period and is adjustable for windage as well as elevation. I will fabricate a base that doesn’t alter the stock and make the mounting fully reversible should I ever find the correct sight. Here I’m drilling and tapping a section of drill rod for the 12-64 threads of the sight’s shaft, and shaping it to fit the existing sight mortise in the stock.


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Once the new base is shaped and fitted to the shaft, I mount it by filing corresponding grooves in the shaft and the inside of the stock’s mortise using file and Dremel tool, and after applying release agent to the shaft, glue the assembly to the stock using thickened epoxy. When the time comes, holding a hot soldering iron against the sight until it reaches 200 degrees or so will release with without damaging the stock, and I’ll have an epoxy-lined hole to work with in mounting a more correct tang sight.

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Test firing the boresighted Jaeger took several shots to get the load in the ballpark. Although these are of large caliber, the old-fashioned barrel twist of one full turn in the barrel’s length is so fast that what would be a normal charge for later patched-ball rifles destroys the patch, the gas seal, and the accuracy. I settled on half the charge one would expect - 60 grains of FFG, a .580 ball with tight, double-patching using .010 prelubed patches, and you can see the difference between inner and outer patches. Test firing was well worth the effort, as I had the frictionless, fly-tumbler lock and set trigger set up too loose, and had to make some adjustments to insure a safe gun. I didn’t chronograph these, but it appears accuracy will be excellent without any further barrel work, and the load fires with enough authority to bruise the shoulder after less than a dozen shots.

All in all, a worthwhile effort, and I look forward to incorporating this Jaeger into my school and even my shooting demonstrations.

[ClaudeH]

Incredible work and tremendous effort to document it for us so well! Thanks, BobSm!

[Dan Shapiro]

Excellent!

[p246]

Thanks Bob keep the hits coming.

[Major Tom]

You Sir are an artist! I thank you for preserving old firearms. Excellent, job well done.

[JBinIll]

Beautifull job.Your photo essay on your restoration techniques and methods is very informative.Thanks for posting.

[Griff Murphey]

Beautiful work by a true artisan and craftsman!

[jon_norstog]

Good going! It's beautiful.

jn

[PeteDavis]

Great restoration.

PD

[JohnMOhio]

Thanks for sharing Bob. I truly enjoy such posts by you. I admire you talent and hope to see additional posts like this from you. A true work of art.

John

[CJCulpeper]

Well done, Sir.

[Ken The Kanuck]

Thank you, most interesting and informative.

KTK

[Fred]

Thanks for posting this most INTERESTING thread!

[Dick Hosmer]

That is one of the best posts I have EVER seen on ANY firearms forum, period!