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WW2 weapons and ordnance collection
- Thread starter DAZ REICH
- Start date
Chapter and verse from Text Book of Ammunition - Projectiles 1954?
"10.5. Materials:The normal material for orthodox British driving bands is copper of a high degree of purity usually conforming to specification BS/STA/13. It has a high heat conductivity, a relatively low melting point, and, in the partially worked condition as in the completed driving band, is relatively soft. It possesses certain disadvantages as a driving band material in that, at velocities of the order of 2,000 f.s., bore friction apparently causes the band surface to melt with a consequent rapid loss of working copper. With high velocity rounds this leads to a tendency to complete band failure in the latter part of shot travel. In high performance guns also, the tendency to band failure reduces the effectiveness of a copper band as a centring device. These effects can be mitigated to an extent by an increase in the cross-sectional area of the band, which may, however, result in excessive band pressure, and will in any case involve a large consumption of copper. In high performance guns copper is therefore an uneconomical material for driving bands, and in very high velocity guns may be entirely unsuitable.
In the Second World War a number of belligerents, owing to a shortage of copper, introduced alternative materials, in particular sintered iron. Sintered iron is produced from iron powder by pressing and heating, the physical properties of the material being controllable over a wide range by selection of the conditions of production. Depending upon the pressure, the temperature, the degree of sub-division, and also the nature of the iron, the product is to a greater or lesser extent spongy in texture, has a bulk density less than that of solid iron, and is in general soft and readily deformed by pressure. It also has a tendency to brittleness, which decreases with increasing solidity.
There is some evidence that, with sintered iron bands and cool propellants, wear at C of R may be appreciably reduced, but abrasive wear throughout the bore, particularly in medium and H.V. guns, may be increased. This latter effect is liable to cause muzzle enlargement with a consequent loss of accuracy, and this might become as important a limiting factor on barrel life with cool propellants as wear at C. of R. It is possible, however, to achieve some reduction in the effects of abrasion by widening the lands and deepening the grooves. Sintered iron has no tendency to be deposited on the bore of the gun, but its low tensile strength prevents its use in large calibre guns owing to break-up under high centrifugal force. As sintered iron has a higher melting point than copper and can be made stronger in shear, it may be possible to use a smaller width of band, which will reduce the band pressure.
Other materials, such as soft iron and mild steel, have been tried and have somewhat similar properties to sintered iron. Soft iron bands are more difficult to engrave, but withstand a greater pressure than copper; they have attained some measure of success in large calibre weapons with high muzzle velocities, where sintered iron would have failed owing to low tensile strength."
"10.5. Materials:The normal material for orthodox British driving bands is copper of a high degree of purity usually conforming to specification BS/STA/13. It has a high heat conductivity, a relatively low melting point, and, in the partially worked condition as in the completed driving band, is relatively soft. It possesses certain disadvantages as a driving band material in that, at velocities of the order of 2,000 f.s., bore friction apparently causes the band surface to melt with a consequent rapid loss of working copper. With high velocity rounds this leads to a tendency to complete band failure in the latter part of shot travel. In high performance guns also, the tendency to band failure reduces the effectiveness of a copper band as a centring device. These effects can be mitigated to an extent by an increase in the cross-sectional area of the band, which may, however, result in excessive band pressure, and will in any case involve a large consumption of copper. In high performance guns copper is therefore an uneconomical material for driving bands, and in very high velocity guns may be entirely unsuitable.
In the Second World War a number of belligerents, owing to a shortage of copper, introduced alternative materials, in particular sintered iron. Sintered iron is produced from iron powder by pressing and heating, the physical properties of the material being controllable over a wide range by selection of the conditions of production. Depending upon the pressure, the temperature, the degree of sub-division, and also the nature of the iron, the product is to a greater or lesser extent spongy in texture, has a bulk density less than that of solid iron, and is in general soft and readily deformed by pressure. It also has a tendency to brittleness, which decreases with increasing solidity.
There is some evidence that, with sintered iron bands and cool propellants, wear at C of R may be appreciably reduced, but abrasive wear throughout the bore, particularly in medium and H.V. guns, may be increased. This latter effect is liable to cause muzzle enlargement with a consequent loss of accuracy, and this might become as important a limiting factor on barrel life with cool propellants as wear at C. of R. It is possible, however, to achieve some reduction in the effects of abrasion by widening the lands and deepening the grooves. Sintered iron has no tendency to be deposited on the bore of the gun, but its low tensile strength prevents its use in large calibre guns owing to break-up under high centrifugal force. As sintered iron has a higher melting point than copper and can be made stronger in shear, it may be possible to use a smaller width of band, which will reduce the band pressure.
Other materials, such as soft iron and mild steel, have been tried and have somewhat similar properties to sintered iron. Soft iron bands are more difficult to engrave, but withstand a greater pressure than copper; they have attained some measure of success in large calibre weapons with high muzzle velocities, where sintered iron would have failed owing to low tensile strength."
The one thing it doesn't mention is that with a muzzle velocity of over 1200fps barrels start to become copper fouled. Which requires the use of de-coopering rounds or the inclusion of a quantity tin/zinc foil in the cartridge case. On firing this effectively vapourises and condenses on the inner surface of the barrel forming a brittle alloy with the copper that is cleared out by the next round.
Tim. G.
Tim. G.
Quatermass
Well-Known Member
Right I've done some futher research and have been given a very interesting document from a friend.
O.K here goes, the picture that stated (or omitted) that the round was not used with the 7.5cm kwk38 L/24 was a U.S. T.M. No. 9-198-3 German explosive ordnance projectiles. March 1953.
I suspect that this was the info that was printed on the web site found by RichardB
I now have a picture of an original (primary refernce source) German manual titled Munition der 7,5 cm Kw.k und Stu.G. 7,5 cm K.
It states that the SprGr 34 was used with the Short 75mm gun.
I apoliges to Daz for any confusion caused.
I still stand by the statement that when buying any sort of ordnance (or anything else for that matter) then its buyer beware and know your stuff. And in my and RichardB's defence we were only trying to help a fellow member. Now wheres that humble pie...
Quatermass.
O.K here goes, the picture that stated (or omitted) that the round was not used with the 7.5cm kwk38 L/24 was a U.S. T.M. No. 9-198-3 German explosive ordnance projectiles. March 1953.
I suspect that this was the info that was printed on the web site found by RichardB
I now have a picture of an original (primary refernce source) German manual titled Munition der 7,5 cm Kw.k und Stu.G. 7,5 cm K.
It states that the SprGr 34 was used with the Short 75mm gun.
I apoliges to Daz for any confusion caused.
I still stand by the statement that when buying any sort of ordnance (or anything else for that matter) then its buyer beware and know your stuff. And in my and RichardB's defence we were only trying to help a fellow member. Now wheres that humble pie...
Quatermass.
