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Having the internet for real world performance instead of trusting calculations from GURPS Vehicles is nice.
Disappointing in some cases, but nice.
The MGM-51A Shillelagh can penetrate 600mm RHAE. That's 6dx8(10) cr ex with a linked 6dx4 cr ex.
The M409 HEAT round can penetrate 530mm RHAE. That's 6dx7(10) cr ex with a linked 5dx4 cr ex.
The fun round is the M625 canister. Ten thousand fletchettes coming from a 152mm short barrel shotgun!
I wonder what gauge 152mm is...
The Math
ReplyDelete152mm=5.98", or nominally a 6-inch bore.
A lead ball that diameter would weigh 46 pounds, give or take a few grains.
So it would be approximately a 0.02 Gauge, or 1/46th of a 1 gauge, which is 1.669", the diameter of a 1# lead ball. (1 gauge means a ball that size would comprise 1#. A 12-ga. bore is the size of a 1/12th pound ball.)
1 ÷ 46 = 0.0217391304347826, which rounds off to 0.02, i.e. 1/46th of a 1 gauge, than which the bore-sized ball is 46x bigger.
For comparison reference, that would make the main guns on the Iowa class BBs (which would accommodate an 880# lead ball of that diameter) a 0.001 gauge bore (precisely, 1 ÷ 880 = 0.0011363636363636, 880X bigger than a 1 gauge).
Lead ball weight of a given diameter = D³ x 1504.56 = wt(gr) ÷ 7000 = ball wt. in pounds.
1 ÷ (given multiple in pounds) = gauge
Didn't know any of that outright, but the steps are findable with mouseclicks.
QED
Now. Since gauge systems tend towards 0 equals the place where the exemplar 1 would be and going larger just adds more zeroes.
DeleteHow many '0's in 152mm's gauge.
As noted above, the Sheridan (or anything similar) is a 0.02 gauge.
DeleteA barrel firing a lead projectile 46x (in weight) that of a 1 gauge, i.e. the number of 152mm lead balls it would take to make a pound would be 0.02 of them.
46 x 0.0217391304347826 = 0.9999999999999996
46 x 0.02 = 0.92
So calling it a 0.02 gauge is close enough for government work.
Thus my old bullet launcher, at 155mm, was close enough to the same gauge (a bare 1/10th of an inch larger) as makes no difference.
But that's why I threw Iowa-class 16"/50 caliber Mark 7 main guns in for comparison.
Three zeros beyond the decimal, compared to the 152mm's one.
Put yet another way: it takes 12 round lead balls the size of a 12 gauge bore to make a pound of projectiles. But it usually only throws 9-15 00 pellets, coming in at an ounce and change (1.11) for Federal's F127 9-pellet 00Buck load, for example.
So the 152mm would accommodate (9x46) 414 such 00 (.33 cal) lead pellets for an equivalent blast.
A Claymore mine, however, puts out 700 1/8th" steel pellets.
So the Sheridan or anything similar becomes a mobile Claymore launcher, for all intents.
But with 10K flechettes instead of round ball bearings per payload?
Fuggedaboudit.
If the Alamo defenders had possessed flechettes, very likely Santa Anna would have limped home after the defeat there, and left stacks of dead soldiers scattered around the mission before retiring.
Your M625 canister round sports a 15.2 pound charge of flechettes.
The biggest Alamo cannon (of 21 various sizes the defenders possessed*) fired an 18# shot.
That would have erased companies wholesale, per round.
The mission could have pumped out about 85K flechettes per volley every time all guns fired.
Cannon grapeshot of the era was generally (Wikipedia shows an exemplar photo showing 8" grapseshot) something like 9 2-inch balls stacked just like pellets are in a 12 ga. buckshot round.
Compared to that weak sauce, facing thousands of flechettes would have been like charging into a woodchipper.
Face first.
*[FWIW, the Alamo's defensive battery was
1x18#
1x16#
1x12#
1x 9#
2x8#
6x6#
4x4#
2x3#
That would mean loads of between 2K and 12K flechettes, per shot.
Even the humble 3-pounders would have been like a triple Claymore going off.
Killing people professionally has become gruesomely scientific.]
Wire and sheet go from 1 to 0 to 00 to 000 to 000 to 0000...
DeleteWhat gauge, using the zeroes convention, is 152mm?
You're, very precisely, missing the fucking joke.
DeleteAh. Got it.
Too inside baseball for me; as neither an engineer nor machinist, I don't play with wire and sheet, obviously, so I didn't get where you were going. And the 20-gauges I play with at work bear no relation to a 20-gauge from Winchester or Remington.
But the answer you were evidently looking for would be something like 46 zeros: 0000000000000000000000000000000000000000000000 gauge.
Probably whittled down to 46/0.
Calling the main gun a 46 aught would probably warm the cockles of my Baby Brother's heart, him having TC'ed a vismod Sheridanski around NTC for a couple of years.
(I notice there's no rhyme nor reason to the increments for AWG, nor for sheet gauge. Just like with fishing hooks. Another mystery for another time.)
AWG and sheet metal gauges DO have a pattern... I even knew what it was once. Long gone from disuse.
DeleteIt's along the same sort of silliness as the shotgun gauge thing.
If we were to be pedantic about it, the Brits would call the 152mm a 46 pounder.