ohland
07-06-2015, 09:08 PM
American Rifleman, vol 69
I see that this is a series by Townsend Whelen. Might be worthwhile to complete all of it. It would make this thread somewhat messy, because I am sure the whole series is bigger than 20k characters, leading to multiple parts...
https://books.google.com/books?id=gJkwAQAAMAAJ&pg=PA613&dq=%2232+wcf%22&hl=en&sa=X&ei=WBybVaCeEsyjsAXYzpTwAQ&ved=0CCUQ6AEwADgK#v=onepage&q=%2232%20wcf%22&f=true
Amateur Gunsmithing (American Rifleman, vol 69, No. 22 Aug 1, 1922 pages 13, 16, 17)
by Major Townsend Whelen
CHAPTER VII
MEASURING THE BORE
It is often quite important to know the diameter of the bore of a firearm. With rifle or pistol one should always know the exact diameter in thousands of an inch of the bore and groove diameter. The bore diameter is the distance from the top of one land to the top of the opposite land, across the diameter. Similarly the groove diameter is the distance from the bottom of one groove to the bottom of the opposite groove. These dimensions will give me an indication as to the probable accuracy of a barrel for any particular kind of ammunition.
The Ordnance Department takes the measurements of the bores of Springfield and Krag rifles with an instrument called a Star Gauge. This is a long rod, bored out to contain another rod inside of it. One end carries projections which fit into the grooves, and the other end carries a scale. The rod is inserted the desired distance into the bore, the scale pushed up until the projections come up tight against the bore on both sides, and the diameter read off the scale. Usually the bore and groove diameters are recorded for every inch of the bore from breech to muzzle, and thus all tight and loose places in the bore can readily be determined. A star gauged rifle is simply one that has been measured. Rifles selected by star gauging are merely those which have been measured and found to come within certain prescribed limits. Star gauges are very expensive, are not for sale, and are entirely beyond the capabilities of the amateur.
But there is another way to measure the bore of a rifle which is nearly as good. This is by driving a bullet through it and measuring the diameter. Select a bullet of pure lead which is several thousandths of an inch larger than the expected groove diameter of the barrel you wish to measure.
It should have a rather short bearing surface. For example, if you wish to measure a .30 caliber barrel about the best bullet to use is the regular factory lead bullet for the .32 W. C. F. cartridge. This bullet is short, of pure lead, and measures .311 inch, which is about .002" larger than the usual groove diameter of .30 caliber barrels. If you have no bullet of the correct size for the barrel you wish to measure it is an easy job to turn several up on a lathe. Clean the barrel thoroughly and lubricate it very lightly with a thin oil like 3 in 1. Have a stiff steel rod about ten inches longer than the bore and almost the diameter of the bore, with a square, blunt tip. See Fig. 1-B. Slightly lubricate the bullet, drop it point first into the chamber, and with the rod shove it about an inch into the rifling. It may be necessary to hit the rear end of the rod a few light blows with a hammer to get it in. Insert the rod from the muzzle, and very carefully press the bullet out again at the breech. Catch it so that it does not fall and deform itself, and measure it with a micrometer caliper. This will give you the groove diameter of the barrel at the breech. In a similar manner, push a bullet into the bore, and with the cleaning rod shove or drive it straight through the bore to within about an inch of the muzzle. Hold the fingers at the muzzle so as to catch the bullet as it comes out, and holding the rod in the other hand, tap light blows on the rear end of the bullet, gradually driving the bullet out at the muzzle. Catch it with the fingers, and measure it with the calipers, thus obtaining the groove diameter at the muzzle. In measuring the bullets, always measure the greatest diameter from the raised portion which has been upset into one groove, to the raised portion opposite. To obtain bore diameter, with a knife very carefully cut away the raised portions on either side of the groove that the lands have impressed on the bullet. Do this on either side of the bullet. Use a very sharp knife, and cut slowly and gingerly so as not to deform or upset the soft lead bullet. Then measure from the bottom of one groove in the bullet to the bottom of the opposite groove, and this will give you the bore diameter.
To determine the smoothness of bore, and to detect and locate any possible tight or loose places in the bore, place the barrel in a heavy vise, using brass jaws so as not to mar the barrel. Force a bullet into the breech as before. Have a good big handle on the rod, or wrap it with a thick cloth. Take ahold of the end of the rod and get the weight of the body behind it. Force the bullet through the bore with a steady motion, as slowly as you can without letting the bullet stop for an instant. It should take two or three seconds for the bullet to pass through. If it goes through with an even and gradual speed, one can feel the difference in pressure which indicate tight or loose places. A little practice is necessary, and one should repeat this test two or three times to be sure of his findings. The best barrels are those which have no tight or loose places, but have even diameters from breech to muzzle, although most riflemen have the opinion that a rifle to shoot lead bullets will do better work if it gets just a very little bit tighter towards the muzzle, being gradually tapered.
To measure the chamber of a rifle it is necessary to make a sulphur cast. The chamber, and about one inch of the rifling forward from it, should be thoroughly cleaned and should have a very slight film of light oil. Take a cork the size of the bore of the rifle, and drill a small hole through its exact center. In this hole place a piece of straight wire, about .0625 inch in diameter. Press the cork into the chamber, and up about half an inch into the rifling, so that the wire extends through the cork and back to a point several inches in rear of the breech. The wire functions as a handle for the cast as the cast is very brittle.
The mixture for the cast is to be made of the following materials:
Sulphur .............................................. 2 ounces
Powdered lamp black......................... 3 grains
Gum camphor dissolved in alcohol ....3 drops
Heat very slowly and stir continually. When the mixture arrives at a thin pouring consistency pour it into the chamber quickly, and allow it to cool thoroughly before removing. To remove, place a cleaning rod in the muzzle and shove lightly on the cork, letting the cast come out slowly, and handling it very gingerly as it is quite brittle.
This cast can now be measured with micrometer and scale, and will give the dimensions of the chamber, as well as its shape. This mixture is almost shrink proof, but it is well to allow .0005 inch for shrinkage.
Plain sulphur may be used instead of this mixture, but it shrinks more, and .002 inch should be allowed for this. It is important that the mixture be heated slowly, other wise it becomes too thick to pour.
REMOVING OBSTRUCTIONS FROM THE BORE
There is no excuse for a trained rifleman ever getting an obstruction in the bore of his rifle or other weapon. There is no danger of this if one takes the proper permutations and uses the proper materials in cleaning, and good ammunition. To avoid getting cleaning rods and patches stuck in the bore, the rod should have the proper size jagged tip (never a slotted one), only new canton flannel should be used for cleaning patches, and the patches should be cut to just the right size so that not more than five pounds pressure is necessary to shove them through the bore. If you use a field cleaner be careful of the size of patch you use with it, and inspect the cord frequently to see that it is not becoming worn or rotten.
143848
Nevertheless novices do continually get obstructions in the bores of their guns, and the amateur gunsmith will often be called upon to remove them. The obstruction may be a cleaning rod and its patch, a .22 caliber bullet in a rim fire rifle, or even worse, a field cleaner and its cord. I was once called upon to remove an obstruction consisting of a stick of wood about eight inches long, a large wad of cloth, and eight ten penny nails, and the man said that he had not done a thing to his rifle.
When you get a rifle with an obstruction in the bore the first thing to do is to pour light oil in at one end, putting in a liberal amount, and letting it soak into the obstruction for about half an hour. Then reverse the barrel, and pour oil in at the other end and let it soak. Then thoroughly clean the bore from each end, down almost to the obstruction. It is then best to dismount the rifle and place the barrel in a heavy vise.
The amateur gunsmith should make two tips for his cleaning rod as shown in Figure 1. One of these tips is formed as a drill, and the other has a perfectly square end, the diameter being just slightly smaller than the bore diameter of the barrel. (This latter tip can also be used in driving bullets through to measure the bore.) Determine the location of the obstruction, and proceed to drive it out the shortest way, using the square ended tip, and driving with light blows of a hammer on the end of the cleaning rod. A little trial will tell one if the obstruction is going to come out by driving or not. In most cases this is all that is necessary, but in some cases it resists all attempts to drive it out. If the obstruction is a lead bullet it can be bored out with the drill.
In some cases, however, so much soft rag may be wedged into the bore that it has to be picked out. Take a steel rod of almost bore diameter, and cut a wood screw thread on one end, about an inch long. Equip the opposite end with a large T" handle. The rod is inserted at either end of the barrel (usually by the shortest route to the obstruction), and the rod rotated by means of the handle, at the same time applying pressure, so as to screw the rod a short distance into the obstruction. Then pull back on the rod and tear loose and pull out a small piece of the obstruction. Continue until it has all been removed.
Care should be exercised in driving the rods, and hard blows particularly should be avoided. Light blows with a hammer, in most cases, will start the obstruction. Heavy blows are apt to only wedge it tighter.
Do not use heat if it can possibly be avoided, as heat is liable to change the character of the steel, and ruin the barrel. In an obstinate case, however, where the barrel is going to be injured anyhow, heating the barrel at the point of the obstruction will expand the bore and loosen the obstruction, or will char the obstruction so that it can be removed.
It must be remembered, however, that in the large majority of cases an obstruction can be removed easily if it be soaked with oil and driven out with the square tip on the rod, and this is the safest method as injury to the barrel is not likely to result.
Once in a great while a cartridge case may rupture in the chamber of a rifle, and upon opening the action the head of the case will come out, leaving the neck, or the neck and a part of the body securely wedged in the chamber. Or the neck may even be carried a little distance into the rifling. Ruptures in cartridge oases are due either to too much head space in the chamber and breech bolt, or to defective brass in the cartridge case. Ruptures almost never occur in a properly made rifle using peace time ammunition, but are of somewhat frequent occurrence when ammunition made in war time is used. There are several broken shell extractors on the market, designed to remove cases which have broken and become wedged in the chamber. They all work on the same principle of entering the broken portion of the case, expanding therein, and having a head by which they can be pulled out with the broken case attached. In their absence the amateur can cut a thread on a steel rod the correct size to enter the case, screw it into the case, and then pull out the broken case with it.
In case the cartridge case breaks at the neck, and a portion of the neck is carried up into the rifling, it will be necessary to drive it out from the muzzle. This can usually be done with a square tip on the cleaning rod as shown in Figure 1-B. Or better still a tip as shown in Figure 1-C, can be used. This latter tip is cut as a female to the rifling, a portion fitting down into the grooves, and the remainder riding on top of the lands. They can be procured for Springfield and Krag rifles, but will have to be made for other types and calibers of rifling. They are very handy in removing all kinds of obstructions from the bore as they fill the bore so completely that everything must be driven before them.
I see that this is a series by Townsend Whelen. Might be worthwhile to complete all of it. It would make this thread somewhat messy, because I am sure the whole series is bigger than 20k characters, leading to multiple parts...
https://books.google.com/books?id=gJkwAQAAMAAJ&pg=PA613&dq=%2232+wcf%22&hl=en&sa=X&ei=WBybVaCeEsyjsAXYzpTwAQ&ved=0CCUQ6AEwADgK#v=onepage&q=%2232%20wcf%22&f=true
Amateur Gunsmithing (American Rifleman, vol 69, No. 22 Aug 1, 1922 pages 13, 16, 17)
by Major Townsend Whelen
CHAPTER VII
MEASURING THE BORE
It is often quite important to know the diameter of the bore of a firearm. With rifle or pistol one should always know the exact diameter in thousands of an inch of the bore and groove diameter. The bore diameter is the distance from the top of one land to the top of the opposite land, across the diameter. Similarly the groove diameter is the distance from the bottom of one groove to the bottom of the opposite groove. These dimensions will give me an indication as to the probable accuracy of a barrel for any particular kind of ammunition.
The Ordnance Department takes the measurements of the bores of Springfield and Krag rifles with an instrument called a Star Gauge. This is a long rod, bored out to contain another rod inside of it. One end carries projections which fit into the grooves, and the other end carries a scale. The rod is inserted the desired distance into the bore, the scale pushed up until the projections come up tight against the bore on both sides, and the diameter read off the scale. Usually the bore and groove diameters are recorded for every inch of the bore from breech to muzzle, and thus all tight and loose places in the bore can readily be determined. A star gauged rifle is simply one that has been measured. Rifles selected by star gauging are merely those which have been measured and found to come within certain prescribed limits. Star gauges are very expensive, are not for sale, and are entirely beyond the capabilities of the amateur.
But there is another way to measure the bore of a rifle which is nearly as good. This is by driving a bullet through it and measuring the diameter. Select a bullet of pure lead which is several thousandths of an inch larger than the expected groove diameter of the barrel you wish to measure.
It should have a rather short bearing surface. For example, if you wish to measure a .30 caliber barrel about the best bullet to use is the regular factory lead bullet for the .32 W. C. F. cartridge. This bullet is short, of pure lead, and measures .311 inch, which is about .002" larger than the usual groove diameter of .30 caliber barrels. If you have no bullet of the correct size for the barrel you wish to measure it is an easy job to turn several up on a lathe. Clean the barrel thoroughly and lubricate it very lightly with a thin oil like 3 in 1. Have a stiff steel rod about ten inches longer than the bore and almost the diameter of the bore, with a square, blunt tip. See Fig. 1-B. Slightly lubricate the bullet, drop it point first into the chamber, and with the rod shove it about an inch into the rifling. It may be necessary to hit the rear end of the rod a few light blows with a hammer to get it in. Insert the rod from the muzzle, and very carefully press the bullet out again at the breech. Catch it so that it does not fall and deform itself, and measure it with a micrometer caliper. This will give you the groove diameter of the barrel at the breech. In a similar manner, push a bullet into the bore, and with the cleaning rod shove or drive it straight through the bore to within about an inch of the muzzle. Hold the fingers at the muzzle so as to catch the bullet as it comes out, and holding the rod in the other hand, tap light blows on the rear end of the bullet, gradually driving the bullet out at the muzzle. Catch it with the fingers, and measure it with the calipers, thus obtaining the groove diameter at the muzzle. In measuring the bullets, always measure the greatest diameter from the raised portion which has been upset into one groove, to the raised portion opposite. To obtain bore diameter, with a knife very carefully cut away the raised portions on either side of the groove that the lands have impressed on the bullet. Do this on either side of the bullet. Use a very sharp knife, and cut slowly and gingerly so as not to deform or upset the soft lead bullet. Then measure from the bottom of one groove in the bullet to the bottom of the opposite groove, and this will give you the bore diameter.
To determine the smoothness of bore, and to detect and locate any possible tight or loose places in the bore, place the barrel in a heavy vise, using brass jaws so as not to mar the barrel. Force a bullet into the breech as before. Have a good big handle on the rod, or wrap it with a thick cloth. Take ahold of the end of the rod and get the weight of the body behind it. Force the bullet through the bore with a steady motion, as slowly as you can without letting the bullet stop for an instant. It should take two or three seconds for the bullet to pass through. If it goes through with an even and gradual speed, one can feel the difference in pressure which indicate tight or loose places. A little practice is necessary, and one should repeat this test two or three times to be sure of his findings. The best barrels are those which have no tight or loose places, but have even diameters from breech to muzzle, although most riflemen have the opinion that a rifle to shoot lead bullets will do better work if it gets just a very little bit tighter towards the muzzle, being gradually tapered.
To measure the chamber of a rifle it is necessary to make a sulphur cast. The chamber, and about one inch of the rifling forward from it, should be thoroughly cleaned and should have a very slight film of light oil. Take a cork the size of the bore of the rifle, and drill a small hole through its exact center. In this hole place a piece of straight wire, about .0625 inch in diameter. Press the cork into the chamber, and up about half an inch into the rifling, so that the wire extends through the cork and back to a point several inches in rear of the breech. The wire functions as a handle for the cast as the cast is very brittle.
The mixture for the cast is to be made of the following materials:
Sulphur .............................................. 2 ounces
Powdered lamp black......................... 3 grains
Gum camphor dissolved in alcohol ....3 drops
Heat very slowly and stir continually. When the mixture arrives at a thin pouring consistency pour it into the chamber quickly, and allow it to cool thoroughly before removing. To remove, place a cleaning rod in the muzzle and shove lightly on the cork, letting the cast come out slowly, and handling it very gingerly as it is quite brittle.
This cast can now be measured with micrometer and scale, and will give the dimensions of the chamber, as well as its shape. This mixture is almost shrink proof, but it is well to allow .0005 inch for shrinkage.
Plain sulphur may be used instead of this mixture, but it shrinks more, and .002 inch should be allowed for this. It is important that the mixture be heated slowly, other wise it becomes too thick to pour.
REMOVING OBSTRUCTIONS FROM THE BORE
There is no excuse for a trained rifleman ever getting an obstruction in the bore of his rifle or other weapon. There is no danger of this if one takes the proper permutations and uses the proper materials in cleaning, and good ammunition. To avoid getting cleaning rods and patches stuck in the bore, the rod should have the proper size jagged tip (never a slotted one), only new canton flannel should be used for cleaning patches, and the patches should be cut to just the right size so that not more than five pounds pressure is necessary to shove them through the bore. If you use a field cleaner be careful of the size of patch you use with it, and inspect the cord frequently to see that it is not becoming worn or rotten.
143848
Nevertheless novices do continually get obstructions in the bores of their guns, and the amateur gunsmith will often be called upon to remove them. The obstruction may be a cleaning rod and its patch, a .22 caliber bullet in a rim fire rifle, or even worse, a field cleaner and its cord. I was once called upon to remove an obstruction consisting of a stick of wood about eight inches long, a large wad of cloth, and eight ten penny nails, and the man said that he had not done a thing to his rifle.
When you get a rifle with an obstruction in the bore the first thing to do is to pour light oil in at one end, putting in a liberal amount, and letting it soak into the obstruction for about half an hour. Then reverse the barrel, and pour oil in at the other end and let it soak. Then thoroughly clean the bore from each end, down almost to the obstruction. It is then best to dismount the rifle and place the barrel in a heavy vise.
The amateur gunsmith should make two tips for his cleaning rod as shown in Figure 1. One of these tips is formed as a drill, and the other has a perfectly square end, the diameter being just slightly smaller than the bore diameter of the barrel. (This latter tip can also be used in driving bullets through to measure the bore.) Determine the location of the obstruction, and proceed to drive it out the shortest way, using the square ended tip, and driving with light blows of a hammer on the end of the cleaning rod. A little trial will tell one if the obstruction is going to come out by driving or not. In most cases this is all that is necessary, but in some cases it resists all attempts to drive it out. If the obstruction is a lead bullet it can be bored out with the drill.
In some cases, however, so much soft rag may be wedged into the bore that it has to be picked out. Take a steel rod of almost bore diameter, and cut a wood screw thread on one end, about an inch long. Equip the opposite end with a large T" handle. The rod is inserted at either end of the barrel (usually by the shortest route to the obstruction), and the rod rotated by means of the handle, at the same time applying pressure, so as to screw the rod a short distance into the obstruction. Then pull back on the rod and tear loose and pull out a small piece of the obstruction. Continue until it has all been removed.
Care should be exercised in driving the rods, and hard blows particularly should be avoided. Light blows with a hammer, in most cases, will start the obstruction. Heavy blows are apt to only wedge it tighter.
Do not use heat if it can possibly be avoided, as heat is liable to change the character of the steel, and ruin the barrel. In an obstinate case, however, where the barrel is going to be injured anyhow, heating the barrel at the point of the obstruction will expand the bore and loosen the obstruction, or will char the obstruction so that it can be removed.
It must be remembered, however, that in the large majority of cases an obstruction can be removed easily if it be soaked with oil and driven out with the square tip on the rod, and this is the safest method as injury to the barrel is not likely to result.
Once in a great while a cartridge case may rupture in the chamber of a rifle, and upon opening the action the head of the case will come out, leaving the neck, or the neck and a part of the body securely wedged in the chamber. Or the neck may even be carried a little distance into the rifling. Ruptures in cartridge oases are due either to too much head space in the chamber and breech bolt, or to defective brass in the cartridge case. Ruptures almost never occur in a properly made rifle using peace time ammunition, but are of somewhat frequent occurrence when ammunition made in war time is used. There are several broken shell extractors on the market, designed to remove cases which have broken and become wedged in the chamber. They all work on the same principle of entering the broken portion of the case, expanding therein, and having a head by which they can be pulled out with the broken case attached. In their absence the amateur can cut a thread on a steel rod the correct size to enter the case, screw it into the case, and then pull out the broken case with it.
In case the cartridge case breaks at the neck, and a portion of the neck is carried up into the rifling, it will be necessary to drive it out from the muzzle. This can usually be done with a square tip on the cleaning rod as shown in Figure 1-B. Or better still a tip as shown in Figure 1-C, can be used. This latter tip is cut as a female to the rifling, a portion fitting down into the grooves, and the remainder riding on top of the lands. They can be procured for Springfield and Krag rifles, but will have to be made for other types and calibers of rifling. They are very handy in removing all kinds of obstructions from the bore as they fill the bore so completely that everything must be driven before them.