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U*AW BOLTS

U*AW BOLTS

inch thick. Taper ream this to be the same taper and diameters as the barrel it is to be used on, then split one side with hack-saw or milling cutter. Slip it over the barrel snugly, then grip it in a pair of pipe jaws in a large vise, setting the vise up as tightly as possible, and use the wrench on the receiver as above. If this split tubing is used on a straight taper barrel it m?.y be made to fit clear back to the breech. However, on a barrel with two or more tapers it would be both difficult and expensive to ream the sleeve to fit; so in such a case fit it far enough forward to get a single straight taper.

When seating new barrels which screw in very tightly, partic- had very excessive headspace for some of the cartridges, for if ularly if one has to set up many barrels of exactly the same type there is anything that takes the greatest skill it is the forming of or outside dimensions, a pair of blocks as shown in Figure 11 IB dies for assuring the exact dimensions of cartridge cases. The result will pay for themselves, although rather expensive to make. Cast- was a most serious accident which crippled the rifleman for life, iron is probably as good material as any for this purpose, and it is and lie was very lucky not to have been killed.

easily machined. A heavy block: is first drilled and then reamed Every gunsmith who undertakes chambering, or the fitting and to fit the barrels, and then split on both sides with milling cutter, threading of barrels should know exactly what he is doing, and

~ , ... . . why; he should have good mechanical ability, and he should be

^ h ^ Tk* V*a y mA -1^ ¿"T ***** thc bcst of tools- are not operations which an profiled Holes for 1/2 inch draw-bolts are drilled, and the de- ^^ ^ do j{ ht the tlmc Nof affi ^ Operations which vice bolted firmly to some solid upright support such as a root riflcnicn tfU5t tQ gllnsmith. p^asers of rifle, should supporting beam in the shop. With a damp o this kind, and the ^ that thcir gun5mith has thc neCessary skill, or else they barrel grooves lapped out and pohshed, barrels already blued may be AouId insfst ^ thcif Hfic bc chambcrcd> md thc rcccivcr ^

screwed into receivers without the slight«* danger of marnng the fitted at a faclQry whcre (herc ^ no doubt whatcver ^at ^

finish. I have not had much success with wooden blocks hollowed ^ ncccssary sk{1] will bc ustd and precaution taken, out to fit the barrel, as perfect contact required for a non-slip grip Bricfly? chambering consists of rcaming out brccch of the can hardly be obtained m wood. Some gunsm.ths use these blocks barrcl with a ^ of flutC(J rcamcrs knQwn ^ chaunbcri rcamcrS|

hollowed out larger than the barrel and lined with heavy leather so as to form the enlargement or chamber into which the cartridge glued m, and dust the surtace of the leather with powdered rosin. The opCratlon „ done graduallyp each reamer in turn being

This method is all right if it works—sometimes it does. slightly larger than the preceding one. Before the last, or finish-

Most .22 caliber barrels are easily removed, as they are usually itlg rcamer is used| thc barrc, b dreaded and fitted to the receiver, not screwed m as tightly as the high power barrels of larger caliber. and finally thc finishing rcamcr is run in to ^^¡y thc righl d ^

Octagon barrels are easy—hold them in an ordinary flat jawed vise in conjunction with a set of headspace gages and the breech block with sheet brass or copper to protect the barrel. ,hat is going to be used in that individual rifle, to be certain that

Be careful in all cases to avoid marring, bending, dentmg or thc chamber is cut to exactly the right depth, and thus assure correct springing the receiver. If it is of a shape which cannot be readily headspadng.

gripped in a smooth jawed wrench without damage, better inlet a lf thc diameten or icngth 0f the chamber be too small the cart-

couple of hardwood blocks to fit its contour, and grip these blocks ridgc win not or it will give Wo bigh—possibly dangerous—

with the wrench. Sometimes a piece of sheet lead wrapped around pressures, or the fired cases will be difficult to extract, and in it will solve the difficulty. In the May 1, 1923, issue of The . American Rifleman, Colonel Stodter offered a method of removing

Krag barrels from actions, which is substantially as follows: addition, unless bullets of a very even and selected diameter be used, it will probably result in an inaccurate barrel. If the diameter of

"The first problem ia to remove the old barrel. Tak« two pieces of wood the chamber be too large the barrel may bc inaccurate, although abouc * x 6 inches and two inches thick and shape them roughly with saw, wc have seen some large chambered rifles shoot with a very fair chisel and rasp to fit on each »¡de of the receiver." » , _ , ** , £ , , . , , J.

"Place the receiver with block, in place in the rise and .crew it up tight dcSrce accuracy; also the life of the barrel will be short due to

»o as to hold the receiver securely. Take a piece of stron« rope about one- £as cuttuig, and thc iired cases will expand so much that they cannot half inch in diameter and twelve to fifteen feet long, double it in thc be reloaded—they may even split. If the chamber be too long, that middle, stick the end of a pick handle or similar piece ofstrongwood through a t00 much headspace, the cartridges may misfire, the primers may the oop and wind the doubled rope smoothly and tightly from near the Mn„. . • . ________® . ,/ . , . , , breech toward the muzzle. Wind the rope in the proper direction so that b}°\ ouf' the cartridge case may separate a half inch m front of when the lever is rotated around the barrcl so as to tighten the rope the the head leaving tile forward portion of the case lodged in the twisting force will be exerted In a counter clockwise direction and tend to chamber, and even the whole head of the case may blow out, allow-

barrel." jng gas t0 cscaj)c {0 the rear, completely wrecking the breech me-

"Hold the rope tightly near the muzzle with one hand and twist the lever • „ , ' . . ... J , , * T , with the other hand. By getting s »houlder under the lever and lifting up chamsm, and perhaps seriously injuring the shooter. In many of great force can be exerted. If this does not get results, heat the receiver the measurements o? the chamber even a few thousandths of an inch

•lightlr with a blow torch ot a candle. This will usually expand it sufficient- njay make all the difference between success and complete failure ly to allow the barrel to be unscrewed." or ¿¡saster.

A word of caution. Remove the bolt or breech mechanism be- . Th.c firi* wewill take up is that of the design of the fore attempting to remove the barreL Such a warning seems su- chamber, that is its dimensions and shape with reference to the perfluous and unnecessary, and should be, but 1 have seen a gunsmith fridge that is to be used. The dimensions and shape of the of thirty-odd years' experience grunt and twist a barrel out by main chamber must be based on the dimensions and shape or the cartndge, strength and awkwardness without even opening the action, break- and thc,klnd, of load tflat <*rtndge contains and must also conform ing off the extractor finally, and cutting a slice out of the breech t?,®ood1 ordnance engineering practice No cartridges arc made with it, and then cuss for ten minutes without repeating himself I absolutely uniformly, but are made with maximum ^id minimum

CHAMBERING: Chambering of rifle barrels is an operation dimensions, the system of inspection at the cartridge factory insur-

9 ing that no cartridge will be produced larger than the maximum measurements, nor smaller than the minimum measurements. The that many gunsmiths mav be called upon to do. If they undertake chamber must be cut to fit and operate safely with either a

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Let the gunsmith make a little slip in design, workmanship, or di- and shape of thc chamber within very close limits, mensions and thc barrel may have no semblance of accuracy, and Unfortunately most gunsmiths are unable to obrain the dimensions what is more important, it may maim or kill thc man who fires it. of maximum and minimum cartridges from thc cartridge makers,

Chambering is inseparably connected with the threading of thc who usually regard their drawings and designs as confidential, barrel, and with headspadng, and these three operations must be Fortunately we can, in most cases, arrive at a very close approxima-

considered together. tion of the dimensions of the maximum and minimum cartridge

At the rime tha: this is being written there has occurred a case from the measurements of a number of standard factory cartridges where a very prominent maker of hand made rifles turned out a of the various makes, the mean of thc measurements of which may rifle for an equally prominent rifleman, which had a little exces- be taken as the average or mean cartridge. These measurements sivc headspace. Moreover the gunmaker acquiesced in the rifle- should not be taken from cartridges of only one make, for these man making his own cases for this rifle by necking down existing may differ from those of some other make slightly, and you want

.30-06 cases in a hand tooL This of course resulted in the cases the rifle to be satisfactory with cartridges of all standard makes, being not uniform, which is exactly thc same as though the rifle Therefore, when starting to design a set of chambering reamers, one should first obtain at least twenty cartridges of all makes of that caliber, and also sometimes all the varieties loaded with different weight bullets. 243

Figure 112 gives the maximum and minimum dimensions of the .30 caliber Ml (.30-06) and the .30 caliber Model 1898 (Krag) cartridges, the measurements being copied from official Ordnance drawings. The mean or average cartridge may be taken as being the mean of these extreme dimensions. Thus if the gunsmith will measure a lot of any other make and size of cartridges, and average these measurements, he arrives at a series of mean measurements for that particular make and caliber of cartridge. Then take half the difference between the maximum and minimum dimensions as shown in Figure 112A or Figure 112B, and add it to these mean dimensions and you have what may be regarded as the maximum dimension of the particular cartridge you are considering. These, then, are the dimensions which you use for the maximum cartridge in considering the design of your chamber. Several hours can profitably be spent with 100 cartridges (20 of each five makes), a micrometer, vernier ruler, pencil, and paper, in determining measurements, and this work should be checked and rechecked to be sure that there is no error anywhere. Do not shirk it. The result will be a drawing of the maximum cartridge for which the chamber should be cut.

Figures 112A and 112B also show the maximum and minimum chamber dimensions for the .30 caliber Ml (Springfield), and the .30 caliber Model 1898 (Krag) chambers. If the chamber is to be cut for some cartridge other than these, there should be the same tolerance between the maximum cartridge selected and determined, and the finishing chambering reamer as there is between the maximum cartridge and the maximum chamber in these drawings. The finishing reamer should always be made to cut the maximum chamber, for as it is used on barrel after barrel it will become dull, will have to be stoned to sharpen it, which will of course reduce its size, and then it must be discarded when it is cutting the minimum chamber, or else ground down for use as one of the preliminary reamers.

A lot of foolishness has been written about minimum or tight chambers. Many shooters seem to think that tight chambers are very desirable, and that they arc more accurate. The truth is that tight chambers are very undesirable. They are fairly accurate only when a bullet of the exactly correct diameter is used, and it is often extremely hard to get such bullets. Chambers cut with the relative dimensions and tolerances shown in the drawings are the most accurate and satisfactory chambers known. Practically every American manufacturer is now designing his chambers for new cartridges with tolerances between maximum cartridge and minimum chamber very closely approximating those shown here, and we cannot too firmly impress upon the gunsmith that he should follow these as a guide.

Very often a customer will write to a gunsmith or a manufac-

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