Talk:8-inch/55-caliber gun

Conversions

I've redone the infobox conversions to begin with American standard units (since this was an American gun) from the cited reference and keep the number of significant figures consistent with that reference.Thewellman (talk) 04:27, 2 December 2011 (UTC)

There are at least four dimensions of possible significance in determining the nominal diameter of naval artillery. The rifled bore has a diameter between the lands which is the diameter before grooves are cut into the barrel. Grooves were generally cut about one-half to one percent of the nominal caliber, so the diameter between grooves would initially be 0.08 in (2.0 mm) to 0.16 in (4.1 mm) larger than the diameter between lands, and both diameters would increase with erosion every time the gun was fired. The projectiles had two critical dimensions. The first was a bourrelet machined into the forward portion of the steel projectile intended to be supported by the rifling lands. The bourrelet was machined to be 0.015 in (0.38 mm) smaller than the nominal land diameter to clear expected fouling remaining in the bore from previous projectiles. There was a copper alloy driving band near the rear of the projectile to be engraved by the rifling. The driving band diameter was at least 0.02 in (0.51 mm) larger than the nominal groove diameter with a tapered lip of even larger diameter to form a competent seal for powder gas within eroded bores. One should also consider the thermal expansion coefficient of steel which would cause bore and projectile diameters to change with temperature. Thewellman (talk) 19:20, 22 August 2021 (UTC)

Rate of fire

Hello! Concerning the rate of fire for the 8 inch 55 caliber guns like the USS Louisville CA 28 had - the USS Louisville #3 pictorial history book states 2.1 rounds per minute. Also, if you watch the Y-tube video it shows the USS Chicago CA 29 loading & firing the guns almost (3) rounds in a minute. Remember the guns have to be lowered to the load postion of about 15 degrees & then elevated to the fire position. (4) rounds a minute is pretty fast & the sailors in this video are really moving just to get (3) per minute. Take care! — Preceding unsigned comment added by TJATTROTTA (talk • contribs) 13:04, 10 May 2017 (UTC)