longcruise
70 Cal.
Diameter is the actual ball diameter and not necessarily the caliber of the barrel. G1 BC is the ballistic coefficient for use in the G1 ballistics table. (G1 is used in the popular and free Point Blank ballistics program). Weight is the actual weight of the ball in the diameter shown and based on being cast or swaged from pure lead, sprues notwithstanding! The gauge is the old time measure of the "caliber" of a barrel and is expressed as balls that will fit the bore that can be obtained per pound of lead.
I don't know when we stopped using "gauge" (even the term "gauge" does not seem to go far back) as bore size and started using caliber in inches. I recall reading references to barrel size as balls per pound in writings from 1847 and of course the "trapdoor" was originally called the Springfield rifle calibre .45 in the 1870's. Maybe a board member can shed more light on this??
Diameter G1 BC Weight Gauge
.720 .083 561 12.46
.710 .082 538 13
.700 .081 516 13.5
.690 .080 494 14.16
.680 .078 473 14.8
.620 .071 358 19.52
.610 .070 341 20.5
.600 .069 325 21.54
.575 .066 286 24.47
.570 .066 278 25.12
.535 .062 230 30.38
.530 .061 224 31.25
.495 .057 182 38.36
.490 .056 177 39.55
.480 .055 166 42.07
.445 .051 132 52.80
.440 .050 128 54.62
.395 .045 93 75.49
.390 .044 89 78.43
.385 .043 86 81.53
.380 .043 83 84.79
.355 .041 67 103.99
.350 .040 64 108.51
.315 .036 47 148.15
.310 .035 45 156.17
.270 .031 30 236.37
.240 .028 21 336.55
I don't know when we stopped using "gauge" (even the term "gauge" does not seem to go far back) as bore size and started using caliber in inches. I recall reading references to barrel size as balls per pound in writings from 1847 and of course the "trapdoor" was originally called the Springfield rifle calibre .45 in the 1870's. Maybe a board member can shed more light on this??
Diameter G1 BC Weight Gauge
.720 .083 561 12.46
.710 .082 538 13
.700 .081 516 13.5
.690 .080 494 14.16
.680 .078 473 14.8
.620 .071 358 19.52
.610 .070 341 20.5
.600 .069 325 21.54
.575 .066 286 24.47
.570 .066 278 25.12
.535 .062 230 30.38
.530 .061 224 31.25
.495 .057 182 38.36
.490 .056 177 39.55
.480 .055 166 42.07
.445 .051 132 52.80
.440 .050 128 54.62
.395 .045 93 75.49
.390 .044 89 78.43
.385 .043 86 81.53
.380 .043 83 84.79
.355 .041 67 103.99
.350 .040 64 108.51
.315 .036 47 148.15
.310 .035 45 156.17
.270 .031 30 236.37
.240 .028 21 336.55
