Tips & Tools with Fred Stutzenberger – Part 20
Tips & Tools #20.Things that Go on the Barrel.
Our rifle must have sights. It must have a touchhole if a flintlock (or a drum and nipple if a caplock). And, if you have not already done it, the barrel must have its underlugs pinned into the stock.
Let’s do the touchhole first. The position and structure of touchhole (also called the vent) have been debated over the years. For years, it had been accepted that the touchhole must be located at the midline of the pan and on the same plane as its rim. Logic dictated that the pan should only be filled up to the hole but never covered, allowing the initial flash to streak across the aerated surface for rapid ignition. Larry Pletcher, in a nicely designed and executed series of electronic measurements, demonstrated that was all poppycock. Larry found that ignition was as fast when the touchhole was covered with priming as it was when the touchhole was left exposed at the surface of the priming or when the priming was placed at the far side of the pan. Larry also determined that the minimal size touchhole for the fastest ignition was 1/16”. Larry has done more fact-finding and dispelled more mythology about flintlock ignition system than anyone I know (See BlackPowderMag.com). I am proud to have co-authored one article with him. Many more of his publications are available online. Good research that is scientifically done and concisely reported.
I drill my touchholes to 0.070” with a #50 bit, but I have observed when using 3Fg powder that a little escapes out into the pan during loading. In the old original rifles, the touchhole was a simple hole leading into the charge. Mike Gaddy showed me a little tool by Tom Snyder that is devised to cone that simple touchhole from the inside so that it looks traditional. You take out the breech plug, slip the little tool through the touchhole from the inside so that the stem sticks out the hole, chuck up the stem in a hand drill and proceed cautiously.
Some breeches were drilled from the off side to allow coning of the hole followed by threading in a plug to seal the hole in the off side. Although that idea allows a nice port for inspection of the breech interior, a removable touchhole liner is easier. The British lined their touchholes with platinum inserts coned from the inside to bring the charge out as close to the priming as possible. For the caplock shooters, I should mention that James Purdey, one of the most famous of the British gunmakers, also put platinum vents into his percussion breeches (Fig. 1) to relieve back pressure.
Touchhole liners nowadays are generally made of stainless steel and last thousands of shots without burning out. Jim Chambers makes a highly regarded White Lightning set of vent liners. I thread my liners 5/16-24, 3/8-24 and 7/16-24. If the threaded section protrudes into the bore of the barrel, it should be relieved at the front of the rim concentric with the bore (Fig. 2) for best powder access. If you are making a flint/percussion convertible, the threaded sections should be identical and the barrel countersunk a bit for best appearance (Fig. 3). I slot my touchhole liners so they can be removed with a screwdriver for cleaning or replacement (Fig. 4). In percussion mode, the nipple should be threaded into the drum as close to the barrel as practical and slanted toward the charge a few degrees (Fig. 5).The drum should be countersunk for the nipple and oriented so that the nipple is aligned squarely with the hammer (Fig. 6). Hammers can be bent slightly one way or another to align properly with the nipple.
Your selection of sights and their positioning on the barrel should be governed by the use of the rifle and the age of your eyes. For the young at heart and keen of eye, choose the simple open iron sight dovetailed into the barrel. I usually mill my rear sights six at a time from 1/2×1/2 x1/8” angle iron. A simple sight is best. Three of my machined sights are shown in Fig. 7. If you don’t like my plain rear sights there are many others to choose from (see suppliers). Track’s Tall Pennsylvania Sight or the Tennessee rear sights are practical and look authentic. One thing about the southern mountain or Tennessee rifle—it had good sights—very simple but wide and slanted backward a bit for shading. Whatever rear sight you get, choose one with a back slant and one that does not require a long dovetail that takes too much metal out of the top of the barrel (and a lot of work too). If competition rules allow, you can easily make an elevation-adjustable rear sight (Fig.8). Of course, the front sight is usually a two-piece German silver set into a brass or copper base (Fig. 8a). I have messed around with a lot of front sights, some I have made and some I have bought (Fig. 8b). Don’t cut the excess base off even though it looks ugly; leave it so you have plenty of base for adjustment and excess material to beat on. It is traditional to drive the sight into the dovetail from the right side of the barrel.
For accurate target work, you can’t beat a hooded globe-type sight. One customer wanted a Jäger rifle with a globe sight (Fig. 9). I thought it looked a bit out of place on that fancy rifle with its horn muzzle cap and gold-banded barrel, but it surely shot very well from the bench. I would have preferred a slightly smaller version for best looks, but pretty is as pretty does.
Most commercial sights have bases about 1/16” thick and 3/8” wide. When cutting the dovetails for your sights by hand, coat the top of the barrel with layout dye and carefully draw guidelines to keep from sawing too deeply or too wide. Track sells a little tool that acts as an offset chisel to shape a square slot across the barrel flat. I cheat by cutting mine on a milling machine using a 0.359” 60° dovetail cutter running at 620 RPM, but you can do a good job by carefully sawing then finishing with a triangular file with one side ground smooth With all the technical schools around the country offering hands on technical courses, you would be wise to inquire about taking a basic machine shop course at night. I thoroughly enjoyed getting my welding degree here at Tri-County Tech. You learn a lot, have the opportunity to do your own projects and meet some really great guys, most of whom are gun nuts just like you. What’s not to like there?
Let’s finish up by talking a little more about attaching the barrel to the stock. I know that I talked about pinning earlier on, but I usually wait until the gun is further along before I pin it in. Besides, you may want to key it in. Installing keys is much harder than pins. With pins, you just drill through and tap a pin into place. With keys you have to make a slot (I showed you some keys before). Start out by carefully positioning your bit over the underlug (Fig. 10) with the barrel firmly clamped against the backstop. Then put it back into its channel and clamp the assembly to the backstop again making sure your index marks align if you are using a swamped barrel. Then carefully spot the entering hole (Fig. 11) with a center drill. If you do not, the bit will likely deflect on entry. The center drill tracks true and leaves a tapered hole. Spot and drill, move over a bit and spot and drill again. Eventually you will have a straight series of holes through the stock and underlug. Now you need to connect the holes. I use a 1/16” diameter end mill, doing one side and then the other until you get the slot as deep as you can on both sides. There probably will be a little web of wood left. You can remove that with a dentist’s burr in a Dremel tool. Ideally, you should use three different bits (Fig. 12): a regular length jobber’s bit for getting positioned, a center drill for spotting and, if you have a thick barrel and stock, an aircraft-length bit that will reach all the way through.
I used to make all my barrel keys, since each one must be fitted individually and marked with a stamped number or a punched code to keep them from getting into the wrong slots. Currently, there are at least 30 different sizes, shapes and styles of barrel keys available from Track so why spend several hours sawing out blanks, forging heads, filing, slotting and finishing keys? Commercial cast keys are more practical and will probably turn out better compared to those from the untrained hand. For specialty keys like the sliver-headed ones on Carolina rifles, I still make my own, but that is beyond the requirements for the first time builder.
If you do choose commercial keys, make sure that they are not too long for your rifle. Most keys are slotted for the installation of keeper pins and if you choose keys that are too long, they will finish out into the slots on skinny-barreled rifles. I put keeper pins in some of my keyed rifles, but when you have the barrel out, you must be very careful that you do not hook something with the heads of those kept keys hanging out of their slots and flapping in the wind.
Once you get your rifle functional (and that is all I expect you to do from the T&T series), you want to have a precise sight that eliminates most of the pilot error in determining the best load for grouping precision. If you have the eye of the eagle, you can disregard the rest of this paragraph. For the rest of us myoptic creatures whose eyes have been blurred by the ravages of aging, we need a better sight, at least at the range when we are working up the best loads. I made an aperture sight (Fig.13) out of scrap metal that is nicely adjustable for windage and that can installed and removed while keeping the permanent screw-in base and my open sight in place. If you do not have means of milling a sight, you can make a temporary range aperture from scrap metal and a disc cut out from a bottle cap (Fig. 14). It has three elevation levels and is held in place by the tang screw and another little wood screw into the wrist behind the tang. It will not stand rough treatment, but is just the thing for precise sighting when working up the best loads for tight groups. It is not terribly sturdy, but if you are careful not to bump it, it will hold up quite well.
The point of working up tightly grouping loads is not accuracy, but rather precision. Remember that accuracy means hitting the target, precision means being able to do it over and over again in the same spot. You can always move the sight to hit the center of the target after you arrive at the best load for grouping precision. A good rifle with a load combination that it likes should cut a five shot one hole group from rest at 50 yards with good eyes and good sightson a wind-still day. But of course, you have to have the groups on the paper. Let’s say that your group is off the paper and into the cardboard, six inches low. Look at Fig. 15 and remember that a/d = b/c where a is the distance from your eye to the rear sight, d is the unknown amount that the rear sight has to be raised, b is the distance to the target and c is the six inch error. Therefore, 20/d = 1800 inches/6 inches = 300,300 d= 20 inches, so d = 0.067 inches upward adjustment to bring the groups into the bulls eye.
Making your first rifle is more learning than doing. There is so much that I have not told you about making a muzzleloading rifle that I am a bit ashamed, mainly because I forgot to include a lot of points when I was writing earlier chapters. There are so many little things I take for granted (or maybe I am just getting absent-minded) so they are omitted in the writing frenzy. I welcome additions, corrections and modifications from other builders, for communication is the lubricant for advancement in any field.
Stutzenberger, Fred. Features of Fast Flintlocks, Muzzle Blasts, Dec., 2013, p.7
Ibid.and Larry Pletcher. A Flash in the Pan,Muzzle Blasts, Oct.,1995, p.50.
Ibid.Making Barrel Keys and Lugs. Part I., Muzzleloader, Nov/Dec.,2003, p.68
Ibid. Making Barrel Keys and Lugs. Part II. Muzzleloader, Jan/Feb. 2004, p.66
Track of the Wolf, 763-633-2500 for an amazing assortment of traditional and modern rifle sights.