back to my original thinkingOctober 3 2015 at 4:22 PM
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|Nelson (no login)|
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Response to another thought
As I conceded yesterday, when I read that an artillery piece is “well worn”, I pretty much automatically conclude bore wear (and I daresay most readers do too), but there are a lot of other parts that can suffer wear, ça va sans dire. Nonetheless, let me pursue my doubt about howitzer bore wear in the years between the two world wars, given the likely minimal firing that occurred. Let’s say the Kiwis got their 3.7-inch mountain howitzers c1923–1925, followed by G.O. 303 in 1926. Of course, then-current howitzers used semifixed rounds with variable charges to achieve different ranges, but during the ‘tween-wars period I imagine that when live firing took place, it was done mostly at 6000 to 7000 yards, i.e., for the very reason I’m arguing, to spare the barrel. The entry level muzzle velocity to achieve that end in the 3.7-inch mountain howitzer was around 300 m/sec (980 ft/sec). With greater loads to achieve greater distances, of course the muzzle velocity increased, and during WWII, supercharge rounds were available for AT use (admittedly uncommon for a small howitzer such as this). Because there was no 3.7-inch field gun in British service, just a few comparative figures from other services to make my point. The data are from Peter Chamberlain and Terry Gander, 1975, Light and Medium Field Artillery, part of Arco Publishing’s WW2 Fact Files series. Because families of ammunition differed, I concede the inexactness of these comparisons. Nonetheless, I’ll attempt to keep them as time-relative and fair as possible.
U.S. M1A1 75mm field howitzer, i.e., on the M3 cavalry-accompanying field carriage: 381 m/sec (1250 ft/sec)
U.S. M1897A4 75mm gun on the M2A3 carriage: 610 m/sec (2000 ft/sec)
Japanese Type 91 105mm howitzer: 546 m/sec (1790 ft/sec)
Japanese Type 92 105mm gun: 760 m/sec (2492 ft/sec)
The three German pieces listed below are of different howitzer versus gun calibers, but used the same field carriage, albeit with a bit of tweaking necessary (I have omitted n.A.—neuer Artillerie—from the designations, because such use for WWII guns differs among various sources).
10.5cm leichte Feldhaubitze 16: 505 m/sec (1657 ft/sec)
7.7cm Feldkanone 16: 600 m/sec (1968 ft/sec)
7.5cm Feldkanone 16: 662 m/sec (2170 ft/sec)
All right the point is made: there is a significant difference in typical muzzle velocities generated by howitzers versus guns, so that during the years of peace, bore wear is generally less in howitzers. In seasonal practice-firings of guns, the summertime soldiers back in the day would often fire mostly subcaliber pieces until the last week, when full-bore firing took place. So, where did all that wear come from in the 3.7-inch mountain howitzers passed on from the Kiwis to the Diggers? Not very much, if any, artillery was extracted during the withdrawals from Greece and Crete, and even if the New Zealanders took 3.7-inch howitzers to North Africa, what chance is there they would have been returned to the SW Pacific? Where during the years of interwar peace or the early couple of years of war could New Zealand’s 3.7-inch mountain howitzers have experienced that kind of wear? Or is the whole thing apocryphal, with the Aussies bellyaching that while the enemy—and to be sure, the Yanks—were equipped with the latest first-line stuff, they had to make do with Kiwi castoffs?