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AN AUTOMATED APPROACH FOR IDENTIFYING CARTRIDGES.

        Cartridges are often recovered from historic archaeological sites. Standard guides to headstamp identification, notably Henry P. White and Burton D. Munhall's Cartridge Headstamp Guide (1977), can be used when headstamps are present. However, early cartridges frequently lack any identifying headstamps, forcing one to rely instead on measurements in an effort to identify the caliber.

        Data presented in the table below have been taken from Frank Barnes' Cartridges of the World (6th Edition, 1989). We have used this spreadsheet to automate cartridge identification in the following fashion. After adding columns to the right side of the spreadsheet, we then write equations in our spreadsheet software to calculate deviations between measured values for base diameter, rim diameter, and case length with tabled values appearing in Barnes. Other measurements, such as shoulder diameter, can be added to the calculations if desired.  As an example, we recently recovered an unheadstamped cartridge near El Paso, TX, exhibiting the following measurements:

                                                                Base = .540         Rim = .458             Case Length = 2.32

        The Euclidean distance is calculated as the square root of the sum of the squared deviations between these three measurements and measurements appearing in the data table. In this instance, for example, the calculations would be:

                    Square Root of  ((Basei -.54)2 + (Rimi - .458)2 + (Case Lengthi - 2.32)2) where i = the ith observation or, in this case, cartridge in the list

        This equation (substituing of course your own measured valued) can then be copied to all of the cartridges in the list.  Identification is accomplished by selecting the match that has the smallest Euclidean distance or the smallest value. In this instance, the smallest value or best match is found with the .30-40 Krag-Jorgensen cartridge. A cross-check of shoulder diameter confirmed this identification.

        Note that cartridge condition directly affects measurements and, by extension, identifications. Don't use really battered cartridges unless there is no other choice. In some instances, we have only been able to measure base diameter (it is very stout) and case length. Even these two measurements can dramatically reduce the number of alternate possibilities that you have to deal with.  Also, try to determine:

        (1) whether the cartridge is a straight or bottlenecked case. 

        (2) whether the cartridge exhibits a rimmed, semi-rimmed, or rimless base. 

These two ancillary pieces of information, combined with a few measurements, can further narrow the field of possible identifications or, if you're very lucky, get a single match. Good luck and have fun! 

Oh, yes!. Tim Seaman, during his sodden, futile efforts to bag an elk during three days of driving rain, reminded me, while sipping Irish whiskey, that I had failed to mention that all these measurements are in inches. I would have thought this obvious since we Americans have refused to go metric. But Tim is the master of clarity and, in deference to his comments, I though I'd point this out. Thank you, Timmy, and better luck next time, you nimrod...



Cartridge/Caliber Case Type Bullet Diam. Neck Diam. Shoulder Dia. Base Diam. Rim Diam. Case Length
22 BB Cap Rim, straight 0.222 0.224   0.224 0.27 0.284
22 CB Cap Rim, straight 0.222 0.225   0.225 0.271 0.42
22 Winchester Auto Rim, straight 0.222 0.25   0.25 0.31 0.665
22 Short Rim, straight 0.223 0.224   0.225 0.273 0.423
22 Long Rim, straight 0.223 0.224   0.225 0.275 0.595
22 Long Rifle Rim, straight 0.223 0.224   0.225 0.275 0.595
22 Extra Long Rim, straight 0.223 0.225   0.225 0.275 0.75
22 Reminoton Auto Rim, straight 0.223 0.245   0.225 0.29 0.663
22 Winchester Mag. RF Rim, straight 0.224 0.24   0.241 0.291 1.052
25 Short Rim, straight 0.246 0.245   0.245 0.29 0.468
25 Stevens Short Rim, straight 0.251 0.275   0.276 0.333 0.599
25 Stevens Rim, straight 0.251 0.276   0.276 0.333 1.125
30 Short Rim, straight 0.286 0.292   0.292 0.346 0.515
30 Long Rim, straight 0.288 0.288   0.288 0.34 0.613
32 Long Rifle Rim, straight 0.312 0.318   0.318 0.377 0.937
32 Extra Short Rim, straight 0.316 0.318   0.317 0.367 0.398
32 Short Rim, straight 0.316 0.318   0.318 0.377 0.575
32 Long Rim, straight 0.316 0.318   0.318 0.377 0.791
32 Extra Long Rim, straight 0.316 0.317   0.318 0.378 1.15
9mm Ball Rim, straight 0.337 0.35   0.35 0.402 0.417
35 Allen Rim, straight 0.342 0.342   0.342 0.407 0.865
38 Short Rim, straight 0.375 0.376   0.376 0.436 0.768
38 Long Rim, straight 0.375 0.376   0.376 0.435 0.873
38 Extra Long Rim, straight 0.375 0.378   0.378 0.435 1.48
41 Short Rim, straight 0.405 0.406   0.406 0.468 0.467
41 Long Rim, straight 0.405 0.407   0.407 0.468 0.635
42 Forehard & Wadsworth Rim, straight 0.417 0.416   0.416 0.485 0.847
41 Swiss Rim, bottleneck 0.418 0.445   0.539 0.62 1.519
44 Short Rim, straight 0.446 0.445   0.445 0.519 0.688
44 Henry Flat Rim, straight 0.446 0.445   0.446 0.519 0.875
44 Extra Long Ballard Rim, straight 0.446 0.456   0.457 0.524 1.25
44 Long Rim, straight 0.451 0.455   0.458 0.525 1.094
46 Long Rim, straight 0.454 0.456   0.456 0.523 1.25
46 Remington Carbine Rim, straight 0.455 0.455   0.455 0.529 0.99
46 Extra Short Rim, straight 0.456 0.458   0.458 0.53 0.633
46 Short Rim, straight 0.456 0.458   0.458 0.53 0.836
50 Ball Carbine** Rim, straight 0.456 0.476   0.56 0.64 0.859
46 Extra Long Rim, straight 0.459 0.457   0.457 0.525 1.534
56-46 Spencer Rim, bottleneck 0.465 0.478 0.555 0.558 0.641 1.035
56-46 Extra Long Rim, bottleneck 0.475 0.468 0.551 0.563 0.638 1.2
46 Hammond Carbine Rim, straight 0.481 0.5   0.518 0.59 1.625
50-60 Peabody** Rim, straight 0.499 0.508   0.559 0.645 1.456
50 Warner Carbine Rim, straight 0.505 0.526   0.526 0.604 0.85
50 Remington Navy Rim, straight 0.51 0.535   0.562 0.642 0.86
50-70 Govt. Rim, straight 0.512 0.532   0.557 0.655 1.72
56-50 Spencer Carbine Rim, straight 0.512 0.543   0.556 0.639 1.156
56-50 Spencer Carbine Rim, straight 0.512 0.543   0.556 0.639 1.156
56-52 Spencer Rifle Rim, straight 0.512 0.54   0.559 0.639 1.035
56-52 Spencer Necked Rim, bottleneck 0.525 0.547 0.558 0.56 0.642 1.02
50 Rem. Pistol** Rim, straight 0.529 0.536   0.558 0.638 0.875
56-56 Spencer Carbine Rim, straight 0.55 0.56   0.56 0.645 0.875
58 Miller Rim, straight 0.585 0.62   0.628 0.709 1.193
219 Zipper Rim, bottleneck 0.224 0.252 0.364 0.421 0.497 1.94
22-15-60 Stevens Rim, straight 0.226 0.243   0.265 0.342 2.01
22 Winchester Centerfire Rim, bottleneck 0.228 0.241 0.278 0.295 0.342 1.39
22 Extra Long Maynard Rim, straight 0.228 0.252   0.252 0.31 1.17
22 Savage High Power Rim, bottleneck 0.228 0.252 0.36 0.416 0.5 2.05
6mm Lee Navy Rimless, bottleneck 0.244 0.278 0.402 0.445 0.448 2.35
25-20 Single Shot Rim, bottleneck 0.257 0.275 0.296 0.315 0.378 1.63
25-21 Stevens Rim, straight 0.257 0.28   0.3 0.376 2.05
25-25 Stevens Rim, straight 0.257 0.282   0.323 0.376 2.37
25 Remington Rimless, bottleneck 0.257 0.28 0.355 0.42 0.421 2.04
25-36 Marlin Rim, bottleneck 0.257 0.281 0.358 0.416 0.499 2.12
256/6.5mm Newton Rimless, bottleneck 0.264 0.29 0.43 0.469 0.473 2.44
275 H&H Magnum Belted, bottleneck 0.284 0.375 0.375 0.513 0.532 2.5
28-30-120 Stevens Rim, straight 0.285 0.309   0.357 0.412 2.51
30-30 Wesson Rim, bottleneck 0.308 0.329 0.33 0.38 0.44 1.66
30-40 Wesson Rim, bottleneck 0.308 0.329 0.381 0.377 0.436 1.63
30 Newton Rimless, bottleneck 0.308 0.34 0.491 0.523 0.525 2.52
32-40 Remington Rim, bottleneck 0.309 0.33 0.358 0.453 0.535 2.13
32-30 Remington Rim, bottleneck 0.312 0.332 0.357 0.378 0.437 1.64
32-35 Stevens/Maynard Rim, straight 0.312 0.339   0.402 0.503 1.88
32-40 Bullard Rim, bottleneck 0.315 0.332 0.413 0.453 0.51 1.85
32 Long CF Rim, straight 0.317 0.318   0.321 0.369 0.82
32 Extra Long Ballard* Rim, straight 0.317 0.318   0.321 0.369 1.24
32 Winchester SL H 0.32 0.343   0.346 0.388 1.28
32-40 Ballard & Win. Rim, straight 0.32 0.338   0.424 0.506 2.13
32 Remington Rimless, bottleneck 0.32 0.344 0.396 0.42 0.421 2.04
32 Ideal Rim, straight 0.323 0.344   0.348 0.411 1.77
33 Winchester Rim, bottleneck 0.333 0.365 0.443 0.508 0.61 2.11
35 Winchester SL H 0.351 0.374   0.378 0.405 1.14
35 Winchester Rim, bottleneck 0.358 0.378 0.412 0.457 0.539 2.41
35 Newton Rimless, bottleneck 0.358 0.383 0.498 0.523 0.525 2.52
350 Griffin & Howe Magnum Belted, bottleneck 0.357 0.382 0.446 0.511 0.528 2.848
35-30 Maynard 1882 Rim, straight 0.359 0.395   0.4 0.494 1.63
35-40 Maynard 1873 Rim, straight 0.36 0.39   0.403 0.764 2.1
35-40 Maynard Rim, straight 0.36 0.39   0.4 0.492 2.06
38-45 Stevens Rim, straight 0.363 0.395   0.455 0.522 1.76
35-30 Maynard 1873 Rim, straight 0.364 0.397   0.403 0.765 1.63
35-30 Maynard 1865 Rim, straight 0.37 0.397   0.408 0.771 1.53
38-40 Remington Rim, straight 0.372 0.395   0.454 0.537 1.77
38-45 Bullard Rim, bottleneck 0.373 0.397 0.448 0.454 0.526 1.8
375 Weatherby Magnum Belted, bottleneck 0.375 0.403 0.495 0.513 0.53 2.86
38 Long Centerfire Rim, straight 0.375 0.378   0.379 0.441 1.03
38 Extra Long Ballard* Rim, straight 0.375 0.378   0.379 0.441 1.63
38-35 Stevens Rim, straight 0.375 0.402   0.403 0.492 1.62
38-50 Maynard 1882 Rim, straight 0.375 0.415   0.421 0.5 1.97
38-56 Winchester Rim, bottleneck 0.376 0.403 0.447 0.506 0.606 2.1
38-50 Ballard Rim, straight 0.376 0.395   0.425 0.502 2
38-50 Remington Rim, straight 0.376 0.392   0.454 0.535 2.23
38-90 Winchester Express Rim, bottleneck 0.376 0.395 0.47 0.477 0.558 3.25
38-70 Winchester Rim, bottleneck 0.378 0.403 0.421 0.506 0.6 2.31
38-72 Winchester Rim, bottleneck 0.378 0.397 0.427 0.461 0.519 2.58
40-50 Sharps (Straight) Rim, straight 0.403 0.421 0.454 0.554 1.88 2.63
40-50 Sharps (Necked) Rim, bottleneck 0.403 0.424 0.489 0.501 0.58 1.72
40-60 Marlin Rim, straight 0.403 0.425   0.504 0.604 2.11
40-63/40-70 Ballard Rim, straight 0.403 0.43   0.471 0.555 2.38
40-65 Ballard Rim, straight 0.403 0.435   0.508 0.6 2.38
40-70 Sharps (Straight) Rim, straight 0.403 0.42   0.453 0.533 2.5
40-70 Sharps (Necked) Rim, bottleneck 0.403 0.426 0.5 0.503 0.595 2.25
40-85/40-90 Ballard Rim, straight 0.403 0.425   0.477 0.545 2.94
40-90 Sharps (Straight) Rim, straight 0.403 0.425   0.477 0.546 3.25
40-90 Sharps (Necked) Rim, bottleneck 0.403 0.435 0.5 0.506 0.602 2.63
40-110 Winchester EX Rim, bottleneck 0.403 0.428 0.485 0.543 0.651 3.25
40-60 Winchester Rim, bottleneck 0.404 0.425 0.445 0.506 0.63 1.87
40-70 Remington Rim, bottleneck 0.405 0.434 0.5 0.503 0.595 2.25
40-70 Winchester Rim, bottleneck 0.405 0.43 0.496 0.504 0.604 2.4
40-65 Winchester Rim, straight 0.406 0.423   0.504 0.604 2.1
40-72 Winchester Rim, straight 0.406 0.431   0.46 0.518 2.6
40-82/40-75 Winchester Rim, bottleneck 0.406 0.428 0.448 0.502 0.604 2.4
401 Winchester SL H 0.406 0.428   0.429 0.457 1.5
40-70 Peabody Rim, bottleneck 0.408 0.428 0.551 0.581 0.662 1.76
40-90 Peabody Rim, bottleneck 0.408 0.433 0.546 0.586 0.659 2
405 Winchester Rim, straight 0.412 0.436   0.461 0.543 2.58
40-75 Bullard Rim, straight 0.413 0.432   0.505 0.606 2.09
40-90 Bullard Rim, bottleneck 0.413 0.43 0.551 0.569 0.622 2.04
40-40 Maynard Rim, straight 0.415 0.45   0.456 0.532 1.78
40-60 Maynard 1882 Rim, straight 417 0.448   0.454 0.533 2.2
40-70 Maynard 1882 Rim, straight 0.417 0.45   0.451 0.535 2.42
44 Evans Short Rim, straight 0.419 0.439   0.44 0.513 0.99
44 Evans Long Rim, straight 0.419 0.434   0.449 0.509 1.54
40-70 Maynard 1873 Rimless, straight 0.422 0.45   0.451 0.759 2.45
40-40 Maynard 1873 Rim, straight 0.422 0.45   0.46 0.743 1.84
40-40 Maynard 1865 Rim, straight 0.423 0.45   0.458 0.766 1.75
44 Henry Rim, straight 0.423 0.443   0.445 0.523 0.88
44-40 Extra Long Rim, bottleneck 0.428 0.442 0.463 0.468 0.515 1.58
44 Long Ballard* Rim, straight 0.439 0.44   0.441 0.506 1.09
44 Extra Long Ballard* Rim, straight 0.439 0.441   0.441 0.506 1.63
44 Extra Long Wesson Rim, straight 0.44 0.441   0.441 0.51 1.63
44-90 Remington Straight Rim, straight 0.442 0.465   0.503 0.568 2.6
44-90 Remington Necked Rim, bottleneck 0.442 0.466 0.504 0.506 0.628 2.44
44-95 Peabody Rim, bottleneck 0.443 0.465 0.55 0.58 0.67 2.31
44-70 Maynard 1882 Rim, straight 0.445 0.466   0.499 0.601 2.21
44-75 Ballard Rim, straight 0.445 0.487   0.497 0.603 2.5
44-100 Ballard Rim, straight 0.445 0.485   0.498 0.597 2.81
44-100 Wesson Rim, straight 0.445         3.38
44-77 Sharps & Remington Rim, bottleneck 0.446 0.467 0.502 0.516 0.625 2.25
44-85 Wesson Rim, straight 0.446         2.88
44-90 Sharps 2.625 Rim, bottleneck 0.446 0.468 0.504 0.517 0.625 2.63
44-60 Sharps & Remington Rim, bottleneck 0.447 0.464 0.502 0.515 0.63 1.88
44-60 Peabody Rim, bottleneck 0.447 0.464 0.502 0.518 0.628 1.89
44-100 Maynard 1873 Rim, straight 0.45 0.49   0.497 0.759 2.88
45-100 Sharps (2.4"-2.6") Rim, straight 0.451 0.489   0.5 0.597 2.5
45-120 Sharps (3.25") Rim, straight 0.451 0.49   0.506 0.597 3.25
45-100 Remington (Necked) Rim, bottleneck 0.452 0.49 0.55 0.558 0.645 2.63
45-50 Peabody Rim, bottleneck 0.454 0.478 0.508 0.516 0.634 1.54
45-60 Winchester Rim, straight 0.454 0.479   0.508 0.629 1.89
45-75 Winchester Rim, bottleneck 0.454 0.478 0.547 0.559 0.616 1.89
45-100 Ballard Rim, straight 0.454 0.487   0.498 0.597 2.81
45-125 Winchester Rim, bottleneck 0.456 0.47 0.521 0.533 0.601 3.25
45 Sharps Straight Rim, straight 0.457 0.478   2.1
45-75 Sharps Rim, straight 0.457 0.478       2.1
45-78 Wolcott Rim, straight 0.457 0.478       2.31
45-80 Sharpshooter Rim, straight 0.457 0.478       2.4
45-90 Winchester Rim, straight 0.457 0.477   0.501 0.597 2.4
45-82 Winchester Rim, straight 0.457 0.477   0.501 0.597 2.4
45-85 Winchester Rim, straight 0.457 0.477   0.501 0.597 2.4
50-90 Sharps Rim, straight 0.509 0.528   0.565 0.663 2.5
50-140 (3.25") Sharps Rim, straight 0.509 0.528   0.565 0.665 3.25
50-110 Winchester Rim, straight 0.512 0.534   0.551 0.607 2.4
50-115 Bullard Semi-rimmed, bottleneck 0.512 0.547 0.577 0.585 0.619 2.19
50-140 Winchester Rim, straight 0.512 0.528   0.551 0.652 3.25
50-50 Maynard 1882 Rim, straight 0.513 0.535   0.563 0.661 1.37
50-95 Winchester Rim, bottleneck 0.513 0.533 0.553 0.562 0.627 1.94
50-70 Maynard 1873 Rim, straight 0.514 0.547   0.552 0.76 1.88
50-70 Government Rim, straight 0.515 0.535   0.565 0.66 1.75
50 Maynard 1865 Rim, straight 0.52 0.543   0.545 0.77 1.24
55-100 Maynard 1882 Rim, straight 0.551 0.582   0.59 0.718 1.94
58 Berdan Musket Rim, straight 0.589 0.625   0.646 0.74 1.75
70-150 Winchester Rim, bottleneck 0.705 0.725 0.79 0.805 0.87 2.18
30-40 Krag Rim, bottleneck 0.308 0.338 0.423 0.457 0.540 2.310