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    "label": "Firing Tables, 75 M/M Gun, Model 1897",
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    "id": "75439557",
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    "title": "Firing Tables, 75 M/M Gun, Model 1897",
    "citationUrl": "https://catalog.archives.gov/id/75439557",
    "collections": [
        "Harry S. Truman Papers Pertaining to Family, Business and Personal Affairs",
        "Military Files"
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            "logicalDate": "1917-12-01",
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    "ocrText": "-2501 12 your\nsof 13 yes.\nthe variations in powder on account of season and temperature, and to\nwear of the guns.\nTable V.\ndp, in weight of projectile, which is approximately stated for each class\nThese tables show, for a given range, the elevation in degrees and ml\nof H. E. shell.\nnutes and in mils, the range scale setting, and the drift in mils.\ndes, in the weight of a liter of air, found from the chart, knowing the\nbarometer aud temperature, and assuming the relative humidity as o.5.\nExample :\nH. E. shell, normal charge, short fuse, range 4300 meters.\n2° Wind. - The wind is resolved into components parallel and perpen-\nThe elevation will be 9°24' or 167 mils, range setting 4725, anl dri\ndicalar to the plane of fire, referred to respectively as Wx and Wy.\n6 mils.\nTables VI.\nTables VII give corrections for these disturbing elements.\nThe values for dV, muzzle velocity, may be used to translate into velocity\nThese tables show, for every 5oo meters of range :\nthe range discrepancies between two pieces (resulting notably from wear),\nto correct for changing powder lots in the same piece, or to correct for\nThe angle of fall in degrees and minutes, and its tangent.\nvariations in powder temperature from one series of firing to another.\nThe value of dVo for a temperature variation is given approximately by\nThe time of flight.\nthe formula\nThe maximum ordinate of the trajectory.\ndV6 = 0.0006 Vo dt.\nThe tangential remaining velocity.\nThe displacement of the point of fall :\nWind corrections are based on a uniform direction and velocity. This\ncondition does not in general obtain. It is therefore necessary to know\nIn range, due to changing the site 1 mil.\nthe velocity and direction of an imaginary wind, which, when taken as\nIn range, due to changing the site 5'.\nconstant, will have the same total effect on the projectile as the actual wind.\nIn height, due to changing the site 5'.\nlis imaginary wind is called the ballistie wind. It varies with the\nmaximum ordinate.\nIn direction, due to changing the deflection P mil.\nThe ballistic wind is determined at meteorological stations for maximam\nThe fuse setting for a o burst in time fire.\nordinates of 5oo, 1000, 2000, 3000, 4000, and 5000 meters. For\nThe displacement of the point of burst in time fire due to a change of os\nintermediate maximum ordinates, the ballistie wind may be computed by\nin the selting.\ninterpolation between the nearest including values furnished.\nThe range and deflection probable errors.\nEse of the tables. - From the manner in which Tables VII are\nThe size of the bracket in degrees and minutes and in meters.\nconstructed, the corrections for existing conditions should be applied to a\nThe angle of opening of shrapnel.\nparticular tabular range to determine the actual range which this range will\nprobably give. The tabular valnes in pange are in Found numbers. For inter-\nmediate ranges, recourse must be had to interpolation.\nT.lles VII.\nThe following method may he used in making this interpolation : Caleu-\nlate the total range variation for two successive tabular ranges which\nThe firing tables have been computed for the normal weights of proj\nbracket the range corresponding to the given elevation. The range to be\ntiles and muzzle velocities given in the front of Tables V. The wind is tak\nexpected from the given elevation may then be obtained by interpolation from\nas o; the weight of a liter of air as 1 gr. 208, which corresponds appre\nthe two corrected ranges obtained. This can generally be done by inspection\nmatefy to a temperature of 15°, a barometer of 750 mm, and a relati\nif the determination is confined to the nearest 25 meters.\nhumidity of o.5.\nBut in practice, the problem is generally the inverse one, to find the\nThese theoretical conditions never exist practically, and in firing the\nrange setting or elevation which will correspond to a given corrected\nlowing disturbing elements are encountered :\nrange.\nThe method is the same as that already described, except that the sign\n1° Variations. - dVo, in muzzle velocity, due to the powder used of of the variations given by Tables VII must be changed. The algebraie sum\nfering more or less from the average of its class (quick, medium, or slow the variations with signs changed (or what is the same thing, the"
}