ohland
06-29-2015, 07:26 PM
This is something I never saw or heard of before today. If someone wishes to argue the usefulness of this bullet, please take it up with Charles Askins.
I now know more about this bullet than I care to. Any further research is up to anyone that wants to know more about it...
v/r,
Lub Monkey
Outdoor Life, vol 17, No. 3, Sep 1918 Pages 198, 200
https://books.google.com/books?id=U_I-AQAAMAAJ&pg=PA144&dq=boat+tail+whelen&hl=en&sa=X&ei=sL-RVcTvJ8HGsAWsuK3QDw&ved=0CDoQ6AEwBg#v=onepage&q=boat%20tail%20whelen&f=true
The Camp McArthur Bullet.
by Charles Askins
The Camp McArthur bullet interested me to the extent that l have made drawings of it, under the impression that it might interest some of our experimental riflemen and bullet designers. In making the drawings, which I did after writing the answer to “Dug and Stats and Leuden," I discovered the lines on which the bullet was designed.
Its lines thruout are apparently the segment of a circle whose radius is four inches. The circle and the way a segment is cut out is shown in figure (1).
143201 Fig. 1.—Bullet's outline is the enclosed segments of two 4 in. circles, about. "A" is rear of bullet, cut off square. “D-C-E" is bearings, in the lands and in grooves. “B” is mark of lands cut in bullet recovered after firing. "C" is groove in bullet to catch surplus bullet-metal shoved to the rear by the lands cutting into bullet. Dotted lines show continuation of construction lines of about two 4-inch circles.
If this design had been carried out the bullet would have been a double ender, with of course the same shape at either end, and the length would have been about two inches and a quarter, depending upon the exact diameter in the middle.
Our boat-shaped missile, it is evident, would have had no bearing against the rifling except amidships. In order to amend this and give the bullet bearing surface, beginning at the middle or the point of greatest diameter of cross section, the lines were extended straight back for half an inch. These lines diverged, as a matter of course, gradually from the curved line on which missile was designed.
Now it is evident that this bullet would have but half an inch of bearing surface instead of the three-quarters of an inch or more which would have been the case with an ordinary bullet. In order to insure a perfect gas-seal a slight enlargement was given the bearing just forward of the groove as shown in figure (2).
143202
Fig. 2.—Boat-shaped basis of bullet. Shaded portions (also in Fig. 1) show where two circular curves are departed from into practically straight lines to give bearings in the rifling.
While I couldn't measure this enlargement or ring of metal accurately, yet it seemed to increase the diameter of the missile at this point somewhere from four to eight thousandths of an inch. A greater part of this enlargement would be cut down by the lands and by the grooves. This is proven by the bullet before me which has been shot—the friction of the grooves against the raised ridge of metal is easily apparent.
Now we come to the cannelure and the reason for it. This cannelure is too far forward to have had the muzzle of the shell crimped into it, for the neck of that shell is only a quarter of an inch long. We must then find other reason for the cannelure. It was evidently placed there as a sort of furrow into which the raised ridge or gas seal could be plowed, compressed and crowded back. It worked, too, for the shallow cannelure (much shallower than is indicated in the drawing), is partly filled up by the metal compressed back into it. This metal thus disposed of would otherwise have been deposited within the bore of the rifle.
Our bullet designer evidently concluded that a full boat-tailed bullet would take up too much room in his case. Therefore he cut off this tall a quarter of an inch behind the rear bearing shoulder, leaving the ball of the shape shown in figure three, and indicated by the crossed line in (1) and (2). He thus reduced the total weight of the missile materially and still retained a certain boat-tailed effect.
143203
Drawing (3) is the bullet enlarged two diameters and drawn to scale, but not very accurately since most of the work is free-hand. I had no proper instruments for making the enlargement accurately. It, however, shows approximately the shape and appearance of the bullet. I enlarged because it was then easier to make the drawing with coarse instruments, and in the enlargement the special features of the missile are more readily noted.
Number (2) is not drawn to scale, and the peculiarities of the bullet, as groove, gas-check ridge and hearing are overdrawn merely for purposes of illustration. What I have endeavored to make clear is the original design and the way it was modified by adding bearing surface, gas-seal, metal catching cannelure, and the point at which the tail was cut off.
This bullet retains balance, for the body is nearly the same length as the point, and yet the friction of bullet body against lands has been reduced as compared with bullets of the usual shape. If a half-inch of bearing surface is enough to insure gas-seal and that the missile cannot be driven across the lands, and if the reduced caliber and shape of the rear portion of this bullet would not further erosion by compressing gas between missile and bore, then the bullet has a superior shape to that of the normal bullet.
The whole bullet is in effect (weight for length at least) a .275 caliber missile fired through a .30 caliber bore, and its length, six times the cross section of the base, would insure a high coefficient. The bearing section of the bullet, as will be noted in drawings (1) and (3) is not an offset from the lines of the point, but instead blends perfectly with those lines, and hence offers no greater air resistance than had the bullet been a true boat-shape.
The point of the bullet before me has been blunted a trifle, apparently by striking something, but originally the missile, carrying out its lines, should have been 1 10-16 inches long. A bullet of this length, .32 caliber, having the ogival point of the ’06 and the usual body, should have weighed 275 grains. I have merely estimated this weight for length and might be mistaken.
Just what the ballistic coefficient of this bullet would be I leave to Mr. Bemis, calculating it on the basis of, length six diameters of the base, point 2-16 inches longer than the body (possibly more than that, for I am measuring from the farthest point forward where land comes in contact with the missile, and the depth of this land means that much bearing on the true point), the weight of the bullet is 200 grains, and we will grant it a velocity of 2,800 feet, which the shell space would apparently guarantee.
The point of this bullet is the best looking wind-splitter that I ever saw, and the balance being carried forward by the peculiar tail ought to insure steadiness of flight, but of course the reduction in weight, owing to form of this bullet, would have an effect on the ballistic coefficient.
Whatever the properties of this bullet when it is a question of maintaining momentum, its peculiar shape certainly does further good internal ballistics. I am not aware of any other bullet which at a velocity of 2,800 feet would permit a bullet length of six diameters. I suppose that five would be about the limit, this perhaps in the .256-140-grain Newton.
CHAS. ASKINS.
Outdoor life, vol 17, No. 5 Nov 1918 page 339 (same file as top article)
More About the “Camp McArthur” Bullet.
Some guns have been made in one odd corner of the world and another that I have never seen. and a few I have never even heard of, strange as that may seem. This cartridge belongs to one class or the other. I have learned, however, that what one man doesn’t know another does, so I am going to describe this bullet, under the assurance that somebody will be able to tell us what gun shoots it.
The bullet is 1 9/16 inches long, with a heavy copper jacket. Nine-sixteenths of an inch from the base it has a shallow cannelure. At the base the bullet is about .275 caliber, as nearly as I could judge. From the base toward the point, the missile gradually enlarges for a quarter of an inch, where there is a slight, tapered shoulder caused by the reduced caliber base merging into the true body of the bullet. This body of the bullet, which alone takes the rifling on being fired, is half an inch long, and the caliber an 8 mm. The diameter might be as large as a .33. The head of the bullet or the point is markedly spitzer, conoidal rather than the ogival we are familiar with in the ’06 bullet, and the length of the point is 13/16 of an inch. Just above the cannelure, for the space of 1/32 inch, the cross-section is enlarged in a sort of ring, where the bullet shows friction. against the grooves. This enlarged ring would apparently prove an effective gas-check.
The whole bullet has superior ballistic qualities, certainly would maintain its initial velocity better than the Springfield or even the 140 grain Newton. I should estimate the coefficient at not less than .550, provided the gun handles the bullet properly. The reduced caliber base is apparently an attempt to give the bullet a semblance of a boat-shaped tail, and it does have the
effect of throwing the center of balance well forward. The bullet ought to be very steady in flight. It weighs exactly 200 grains.
The shell is rimmed, an unusually heavy rim. The total length of the case is two inches,'of which 5/16 of an inch is neck. The shell is 10/16 across the rim, 9/16 at the base under the rim, tapering thence to 7/16 at the shoulder, not a very even taper at that, since there is a sudden contraction about midway. The diameter of the neck at the mouth (outside diameter) is 11/32 of an inch. The powder capacity is some grains greater than the Newton .256. The shell is marked on the base, R. A., and on the opposite side, 84-17. This sounds like a scientist trying to describe the first ******* he had ever seen, but come on with your answer—Chas. Askins.
Note—Before me, as I write this, is a cartridge, and also a bullet, said to be the regular ammunition of the French army. The “Camp McArthur" bullet described by Mr. Asklns above, and
also pictured in September Outdoor Life, while different in some respects. yet so closely resembles this French army bullet before me that I venture the guess—a mere guess, mind you—that the “Camp McArthur" bullet is really a parle vous. For further in formation I refer Mr. Askins. et al., to Heine, Fritz & Co., Rhineward, Northern France. C. T.
Wowser.
American Rifleman, vol64, No. 10, 1 June 1918, pages 133-135
https://books.google.com/books?id=to4wAQAAMAAJ&pg=PA184&dq=%22camp+macarthur+bullet&hl=en&sa=X&ei=5tSRVZnHBIrDsAWBioC4DA&ved=0CEUQ6AEwCA#v=onepage&q=%22camp%20macarthur%20bullet&f=false
Improving the Coefficient
by Charles Askins
143205
Drawing No. (5) is taken from an actual bullet sent me by some soldiers .stationed at Camp McArthur, Texas. The troopers sent me both bullet and shell, wishing to know what gun handled them.
The shell is 2 inches long, large, heavily rimmed, well tapered, and bottle-necked, with a powder capacity greater than that of the Springfield. The bullet is an 8 mm., and the drawing here shown has little reference to scale, being drawn too long for its cross section. The bullet had actually been shot, for the marks of the lands were on it. Calculating from the marks of the lands, the twist of the rifle was one turn in 8 inches.
The reason for my including this bullet among those shown is that it is the nearest to a boat-shaped of any missile that I have ever seen. bullet is evidently based on a purely boat-shaped basis, the lines being the segment of a circle whose radius is about 5 inches. Naturally, a boatshaped projectile would have little bearing on the rifling, so the designer added bearing. Beginning amidships, or a trifle back of that, he bore away from the curve with straight lines which continued back for half an inch, thence sloped into the true lines of the bullet as shown at the shoulder. A quarter of an inch back of the shoulder, the tail of the bullet was cut square ofl, the bullet there being of a diameter of a quarter of an inch.
A peculiar thing about this bullet is that it has an enlargement of the bearing diameter of about .008 thousandths of an inch just forward of the shallow groove shown in the drawing. This enlargement seems to be intended for a positive gas-check, a positive means of preventing gas cutting, and the groove is placed there to catch the metal as it is condensed and driven back by the action of both lands and grooves. This is shown by the fact that the cannelure was partly filled after the bullet was fired. Lacking this cannelure, the compressed metal of this enlarged rim would have been deposited within the bore.
This bullet is markedly Spitzer, with a point conoidal in shape, the longest and sharpest point that I have ever seen on a bullet, from its design the point being necessarily considerably longer than the body. The surface bearing on the lands is but half an inch in length, which would materially reduce friction; and yet the bearing seems ample-—bullet itself shows after being shot that it had no tendency to drive across the lands. The bullet weighed exactly 200 grains, while if it had been of the usual shape the weight would have been from 25 to 50 grains more. In this bullet a unique and well-calculated attempt was made to promote high coefficiency, and in my opinion the designer must have succeeded. Doubtless the tail of the bullet was cut off reluctantly, through the need of conserving powder space. The powder space in the case warrants the belief that the bullet could have been driven at a velocity of from 2,800 to 3,000 feet.
I now know more about this bullet than I care to. Any further research is up to anyone that wants to know more about it...
v/r,
Lub Monkey
Outdoor Life, vol 17, No. 3, Sep 1918 Pages 198, 200
https://books.google.com/books?id=U_I-AQAAMAAJ&pg=PA144&dq=boat+tail+whelen&hl=en&sa=X&ei=sL-RVcTvJ8HGsAWsuK3QDw&ved=0CDoQ6AEwBg#v=onepage&q=boat%20tail%20whelen&f=true
The Camp McArthur Bullet.
by Charles Askins
The Camp McArthur bullet interested me to the extent that l have made drawings of it, under the impression that it might interest some of our experimental riflemen and bullet designers. In making the drawings, which I did after writing the answer to “Dug and Stats and Leuden," I discovered the lines on which the bullet was designed.
Its lines thruout are apparently the segment of a circle whose radius is four inches. The circle and the way a segment is cut out is shown in figure (1).
143201 Fig. 1.—Bullet's outline is the enclosed segments of two 4 in. circles, about. "A" is rear of bullet, cut off square. “D-C-E" is bearings, in the lands and in grooves. “B” is mark of lands cut in bullet recovered after firing. "C" is groove in bullet to catch surplus bullet-metal shoved to the rear by the lands cutting into bullet. Dotted lines show continuation of construction lines of about two 4-inch circles.
If this design had been carried out the bullet would have been a double ender, with of course the same shape at either end, and the length would have been about two inches and a quarter, depending upon the exact diameter in the middle.
Our boat-shaped missile, it is evident, would have had no bearing against the rifling except amidships. In order to amend this and give the bullet bearing surface, beginning at the middle or the point of greatest diameter of cross section, the lines were extended straight back for half an inch. These lines diverged, as a matter of course, gradually from the curved line on which missile was designed.
Now it is evident that this bullet would have but half an inch of bearing surface instead of the three-quarters of an inch or more which would have been the case with an ordinary bullet. In order to insure a perfect gas-seal a slight enlargement was given the bearing just forward of the groove as shown in figure (2).
143202
Fig. 2.—Boat-shaped basis of bullet. Shaded portions (also in Fig. 1) show where two circular curves are departed from into practically straight lines to give bearings in the rifling.
While I couldn't measure this enlargement or ring of metal accurately, yet it seemed to increase the diameter of the missile at this point somewhere from four to eight thousandths of an inch. A greater part of this enlargement would be cut down by the lands and by the grooves. This is proven by the bullet before me which has been shot—the friction of the grooves against the raised ridge of metal is easily apparent.
Now we come to the cannelure and the reason for it. This cannelure is too far forward to have had the muzzle of the shell crimped into it, for the neck of that shell is only a quarter of an inch long. We must then find other reason for the cannelure. It was evidently placed there as a sort of furrow into which the raised ridge or gas seal could be plowed, compressed and crowded back. It worked, too, for the shallow cannelure (much shallower than is indicated in the drawing), is partly filled up by the metal compressed back into it. This metal thus disposed of would otherwise have been deposited within the bore of the rifle.
Our bullet designer evidently concluded that a full boat-tailed bullet would take up too much room in his case. Therefore he cut off this tall a quarter of an inch behind the rear bearing shoulder, leaving the ball of the shape shown in figure three, and indicated by the crossed line in (1) and (2). He thus reduced the total weight of the missile materially and still retained a certain boat-tailed effect.
143203
Drawing (3) is the bullet enlarged two diameters and drawn to scale, but not very accurately since most of the work is free-hand. I had no proper instruments for making the enlargement accurately. It, however, shows approximately the shape and appearance of the bullet. I enlarged because it was then easier to make the drawing with coarse instruments, and in the enlargement the special features of the missile are more readily noted.
Number (2) is not drawn to scale, and the peculiarities of the bullet, as groove, gas-check ridge and hearing are overdrawn merely for purposes of illustration. What I have endeavored to make clear is the original design and the way it was modified by adding bearing surface, gas-seal, metal catching cannelure, and the point at which the tail was cut off.
This bullet retains balance, for the body is nearly the same length as the point, and yet the friction of bullet body against lands has been reduced as compared with bullets of the usual shape. If a half-inch of bearing surface is enough to insure gas-seal and that the missile cannot be driven across the lands, and if the reduced caliber and shape of the rear portion of this bullet would not further erosion by compressing gas between missile and bore, then the bullet has a superior shape to that of the normal bullet.
The whole bullet is in effect (weight for length at least) a .275 caliber missile fired through a .30 caliber bore, and its length, six times the cross section of the base, would insure a high coefficient. The bearing section of the bullet, as will be noted in drawings (1) and (3) is not an offset from the lines of the point, but instead blends perfectly with those lines, and hence offers no greater air resistance than had the bullet been a true boat-shape.
The point of the bullet before me has been blunted a trifle, apparently by striking something, but originally the missile, carrying out its lines, should have been 1 10-16 inches long. A bullet of this length, .32 caliber, having the ogival point of the ’06 and the usual body, should have weighed 275 grains. I have merely estimated this weight for length and might be mistaken.
Just what the ballistic coefficient of this bullet would be I leave to Mr. Bemis, calculating it on the basis of, length six diameters of the base, point 2-16 inches longer than the body (possibly more than that, for I am measuring from the farthest point forward where land comes in contact with the missile, and the depth of this land means that much bearing on the true point), the weight of the bullet is 200 grains, and we will grant it a velocity of 2,800 feet, which the shell space would apparently guarantee.
The point of this bullet is the best looking wind-splitter that I ever saw, and the balance being carried forward by the peculiar tail ought to insure steadiness of flight, but of course the reduction in weight, owing to form of this bullet, would have an effect on the ballistic coefficient.
Whatever the properties of this bullet when it is a question of maintaining momentum, its peculiar shape certainly does further good internal ballistics. I am not aware of any other bullet which at a velocity of 2,800 feet would permit a bullet length of six diameters. I suppose that five would be about the limit, this perhaps in the .256-140-grain Newton.
CHAS. ASKINS.
Outdoor life, vol 17, No. 5 Nov 1918 page 339 (same file as top article)
More About the “Camp McArthur” Bullet.
Some guns have been made in one odd corner of the world and another that I have never seen. and a few I have never even heard of, strange as that may seem. This cartridge belongs to one class or the other. I have learned, however, that what one man doesn’t know another does, so I am going to describe this bullet, under the assurance that somebody will be able to tell us what gun shoots it.
The bullet is 1 9/16 inches long, with a heavy copper jacket. Nine-sixteenths of an inch from the base it has a shallow cannelure. At the base the bullet is about .275 caliber, as nearly as I could judge. From the base toward the point, the missile gradually enlarges for a quarter of an inch, where there is a slight, tapered shoulder caused by the reduced caliber base merging into the true body of the bullet. This body of the bullet, which alone takes the rifling on being fired, is half an inch long, and the caliber an 8 mm. The diameter might be as large as a .33. The head of the bullet or the point is markedly spitzer, conoidal rather than the ogival we are familiar with in the ’06 bullet, and the length of the point is 13/16 of an inch. Just above the cannelure, for the space of 1/32 inch, the cross-section is enlarged in a sort of ring, where the bullet shows friction. against the grooves. This enlarged ring would apparently prove an effective gas-check.
The whole bullet has superior ballistic qualities, certainly would maintain its initial velocity better than the Springfield or even the 140 grain Newton. I should estimate the coefficient at not less than .550, provided the gun handles the bullet properly. The reduced caliber base is apparently an attempt to give the bullet a semblance of a boat-shaped tail, and it does have the
effect of throwing the center of balance well forward. The bullet ought to be very steady in flight. It weighs exactly 200 grains.
The shell is rimmed, an unusually heavy rim. The total length of the case is two inches,'of which 5/16 of an inch is neck. The shell is 10/16 across the rim, 9/16 at the base under the rim, tapering thence to 7/16 at the shoulder, not a very even taper at that, since there is a sudden contraction about midway. The diameter of the neck at the mouth (outside diameter) is 11/32 of an inch. The powder capacity is some grains greater than the Newton .256. The shell is marked on the base, R. A., and on the opposite side, 84-17. This sounds like a scientist trying to describe the first ******* he had ever seen, but come on with your answer—Chas. Askins.
Note—Before me, as I write this, is a cartridge, and also a bullet, said to be the regular ammunition of the French army. The “Camp McArthur" bullet described by Mr. Asklns above, and
also pictured in September Outdoor Life, while different in some respects. yet so closely resembles this French army bullet before me that I venture the guess—a mere guess, mind you—that the “Camp McArthur" bullet is really a parle vous. For further in formation I refer Mr. Askins. et al., to Heine, Fritz & Co., Rhineward, Northern France. C. T.
Wowser.
American Rifleman, vol64, No. 10, 1 June 1918, pages 133-135
https://books.google.com/books?id=to4wAQAAMAAJ&pg=PA184&dq=%22camp+macarthur+bullet&hl=en&sa=X&ei=5tSRVZnHBIrDsAWBioC4DA&ved=0CEUQ6AEwCA#v=onepage&q=%22camp%20macarthur%20bullet&f=false
Improving the Coefficient
by Charles Askins
143205
Drawing No. (5) is taken from an actual bullet sent me by some soldiers .stationed at Camp McArthur, Texas. The troopers sent me both bullet and shell, wishing to know what gun handled them.
The shell is 2 inches long, large, heavily rimmed, well tapered, and bottle-necked, with a powder capacity greater than that of the Springfield. The bullet is an 8 mm., and the drawing here shown has little reference to scale, being drawn too long for its cross section. The bullet had actually been shot, for the marks of the lands were on it. Calculating from the marks of the lands, the twist of the rifle was one turn in 8 inches.
The reason for my including this bullet among those shown is that it is the nearest to a boat-shaped of any missile that I have ever seen. bullet is evidently based on a purely boat-shaped basis, the lines being the segment of a circle whose radius is about 5 inches. Naturally, a boatshaped projectile would have little bearing on the rifling, so the designer added bearing. Beginning amidships, or a trifle back of that, he bore away from the curve with straight lines which continued back for half an inch, thence sloped into the true lines of the bullet as shown at the shoulder. A quarter of an inch back of the shoulder, the tail of the bullet was cut square ofl, the bullet there being of a diameter of a quarter of an inch.
A peculiar thing about this bullet is that it has an enlargement of the bearing diameter of about .008 thousandths of an inch just forward of the shallow groove shown in the drawing. This enlargement seems to be intended for a positive gas-check, a positive means of preventing gas cutting, and the groove is placed there to catch the metal as it is condensed and driven back by the action of both lands and grooves. This is shown by the fact that the cannelure was partly filled after the bullet was fired. Lacking this cannelure, the compressed metal of this enlarged rim would have been deposited within the bore.
This bullet is markedly Spitzer, with a point conoidal in shape, the longest and sharpest point that I have ever seen on a bullet, from its design the point being necessarily considerably longer than the body. The surface bearing on the lands is but half an inch in length, which would materially reduce friction; and yet the bearing seems ample-—bullet itself shows after being shot that it had no tendency to drive across the lands. The bullet weighed exactly 200 grains, while if it had been of the usual shape the weight would have been from 25 to 50 grains more. In this bullet a unique and well-calculated attempt was made to promote high coefficiency, and in my opinion the designer must have succeeded. Doubtless the tail of the bullet was cut off reluctantly, through the need of conserving powder space. The powder space in the case warrants the belief that the bullet could have been driven at a velocity of from 2,800 to 3,000 feet.