105mm question

This is a 105mm howitzer in front of Newburgh NY National Guard building. It is made in 1941 (barely seen from overpainting). Question: Why 105mm and not customary inches? Was that a European design (like Oerlickon) or they just felt metric in 1941? Was there a pre-existing 105mm ammo to which the gun was made?

It seems to me that Army-types in big guns were, in that era, all in metric measurement, unlike Navy pieces. I am thinking of the various “artillery” we saw as grunts (I was never a lanyard puller) - 60mm Mortar, 81mm Morter, 57mm Recoiless Rifle, 90mm Tank gun, 75mm Recoiless Rifle, 105mm Recoiless rifle (later changed to 106mm I think, but that was after my service). The only piece I can think of that we knew about as Infantrymen, above .50 caliber, was the 4.2" Chemical Mortar. I never understood why, as I recall anyway, everything to do with those was under the auspices of the Chemical Corp, when the fired HE rounds as much or more than other types of projectiles. Soemone with wider infantry experience than I woould have to answer that, or an ex-4.2" mortarman. We knew about them, but I never actually saw a 4.2" Mortar in the Army except in Army Day “museum-type” displays.

that’s just a common soldier’s view - nothing technical about my answer, I know. Not into the big stuff collecting and have never really studied it.

Vlad–I can’t speak to the other big calibers, but there was a 8 inch Field Artillery as well as the 4.2 inch John mentioned. Also, most of the big Coastal Defence guns were inch rated, but then most of those, although operated by the Army, were adopted Naval guns mounted on land based carrages.

As for the 105 Howitzer, it is metric because it is an adopted design from the French since before WW-I. I think it dates back in the basic design of the case to about 1895.

English cannon in the17th Century was generally classed by caliber in inches while Continental cannon of the same period used the weight of the projectile (caliber in pounds).

By the 18th Century most field artillery was classed using the caliber by weight system although seacoast artillery, and some seige artillery and mortars were designated by bore size in inches.

Until the introduction of rifled artillery in the 19th Century which were classed by bore size in inches, except for some British and French rifles which continued to use the projectile weight.

Then, in that same 19th Century, along came the Metrics.

My point? Don’t try to make sense of it. You’ll go nuts because there isn’t any sense to be made.



To your list of “Infantry inch” weapons, in WW-2 we used the M6A1 2.36" Bazooka (even though that translates to 60mm, it was designated in inches) and post war switched to the M29A2 3.5" Bazooka