Talk:QF 4.7-inch Mk XI naval gun

March

March is a highly respected source that has 539 pages of text and dozens of line drawings and he quotes directly from many admiralty documents and ship's action reports. It is standard wikipedia policy to place information from respected sources that contradict the text into footnotes, so that the reader can be made aware that some respected sources differ on specific details. I have been involved in many edit discussions where this has been done, and it is extremely rare for someone to remove a footnote that does not change the text of the article.Damwiki1 (talk) 20:44, 17 September 2011 (UTC)

March is significantly flawed, not only in my opinion, but that's neither here nor there. I'd missed that you'd reinserted it as a footnote, and that's fine, as you say. Although I wonder how March got 12 rpm with a firing cycle of 6 seconds and no on-mount ready ammo. Hard to override the firing cycle when you've got a power rammer. I've cleaned up your quote to make everything match.

The nominal and widely quoted maximum rate of fire of the 4.7 Mk12 is 10 to 12 rounds per minute. March quotes directly from trials and action reports to show that much shorter cycle times were possible and that 12 RPM could be maintained over long periods of time. It is possible that March ran across similar info for the Mk XI gun and/or that the hoist and rammer speeds could be improved upon by experienced crews, which in my readings, seems to be typical for many weapons, from most nations. For example the 4.7in Mk VIII showed a steady increase (see pdf page 142) in the rate of fire in the 1930s as crews gained more experience with the weapon. In any event, I guess I should have started this discussion sooner. Sorry for any troubles.Damwiki1 (talk) 21:18, 17 September 2011 (UTC)

Interesting, I didn't think that the firing cycle times could be adjusted by the crews, but my only experience is with 25 mm autocannon and 105 and 155 mm howitzers. Both of which differ significantly from these naval mounts. I've requested to borrow March, so I can see what he's got to say myself.--Sturmvogel 66 (talk) 21:34, 17 September 2011 (UTC)

I think you will find March to be a very interesting read. I often come across statements regarding maximum or extended maximum rates of fire for various weapons. This source states:
"Arthur Chubb vividly remembers this action "...we had been closed up at action stations all evening, I was in 'B' turret. When we attacked this particular ship we fired about 180 rounds in ten minutes - which was very hard work. When we stopped firing we went out onto the gun deck and I can remember seeing all of the empty shell cases around us..."."

and firing 9rpm/gun for 10 minutes indicates that a shorter cycle time, over a couple of minutes, seems possible. Campbell, page 47 indicates at least five rounds of ready use ammo per gun (2 near the loading tray and 3 against the back of the turret) was available to the loader and the drawing of the mounting in Smith, p48-49 indicates 10 rounds of ready use ammo per gun - two rounds by the loading tray and 8 more rounds/gun against the back of the turret. By way of comparison in terms of rate of fire, the USN recommended a 10rpm RoF for the 5"/38 during shore bombardment over a 10 minute period, where the RoF over two - five minutes might be much higher. USS Samuel B. Roberts was able to fire 325 rounds from one 5in/38 gun over 35 minutes, before the gun overheated and exploded on the 2nd to last round. Robert Hughes in Flagship to Murmansk states that Scylla's forward 4.5in UD mounts were able to sustain 16 rpm during at least one AA action, while In Alarm Starboard, Brooke states that he was able to achieve a loading cycle "...of 4 and a half to 5 seconds..." at low elevaton as OIC of a 6in triple turret on HMS Bermuda, where the 6in manual states a typical maximum of 8 RPM: [1] (paragraph 17). So variability of rate of fire was a common occurrence and depended on the context and only action reports, where specific salvo intervals are stated, can really provide hard and fast answers, especially as the AFCC and HACS/FKC could specify salvo interval time, and the AFCC even had a salvo timing stop watch.Damwiki1 (talk) 23:19, 17 September 2011 (UTC) ::Actually during shore bombardment they recommended 10 rpm/5 minutes, as per the reference. Damwiki1 (talk) 01:26, 18 September 2011 (UTC)