So whilst I think there was a lot of good stuff in that post I just don't see the 75mm happening for Britain at this point. I feel I need to add the disclaimer here that this is NOT about the merits of the 75mm. The 75mm is a very good gun for 40-42, I do not dispute that. The issue I have had throughout all of this is that any attempts to get the UK to adopt the 75mm earlier than they did OTL run up against both Official and Doctrinal resistance along with logistical issues around actually building the guns and ammo in Britain which will need to be done before 1942 and the US entry into the war.
Fair enough, don't disagree.
Now to the actual post. Firstly as
@marathag points out, the 75mm Britain has just got probably wont fit. See this post.
Or if it could be made to fit then it needs a bit of work first. That will not only slow down the initial fitting of the Gun to the Valiant but also the process of converting the guns to put them into Valiant's if it were to become an adopted practice making the whole process less appealing.
The issue confronting Carden is that there's a demand for HE, the 3-inch howtizer isn't ready, all they have is the 3.7-inch howitzer. Looking at the M1898 is an alternative that will be rejected for the very reasons you mention.
Then we have the issue of securing the Guns themselves. You are asking the Royal Artillery to give up guns they need so that Vickers can see if they can fit in a tank and if they do fit we want a few hundred off you so we can put them in tanks. I can not see the RA looking too kindly on that. these are guns Britain feels it needs right now as artillery pieces, not experimental tank guns. Yes getting one or two to experiment with may be a possibility but in the short to medium term getting many more will be very difficult. OTL the guns were in service to 1945 as coastal artillery so they were felt to have a place. Even as they go from being home defence front line issue they will likely go to training roles etc. That again is a valuable role for the guns for Britain. Getting them will not be easy.
Absolutely, which is another part of the reason that this won't work.
Next we come to where we are in the war, its July 1940, the 25th to be precise. We are 15 days into the Battle of Britain, past the nuisance raid stage and into the shipping attacks and night time bombings. Invasion fear and preparation will be real despite the improvements in France. At this point Britain is still very short of Heavy equipment and will want to maximise its production as much as possible. Carden looking to tinker with a new, interim CS tank gun will be looked at poorly I suspect. Even if it isn't, even if Carden has the pull to get the guns to experiment with it will be a fair few months before the mounting is ready, the guns have been pried from the hands of the RA and the situation has calmed down enough for Britain to really start thinking about switching up production from things already being built or in the works. That takes you probably into 1941 so not far from the 3" being ready anyway. That kind of makes the whole process of developing a stop gap weapon redundant if it wont really be ready much sooner than the weapon it is meant to be filling in for.
All true and valid points. The only outcome of the failed experiment should be helpful to the Victor, of having worked on a mounting for the gun being developed from the Vickers 75mm AA gun, which will be basically OTL's 77mmHV.
We also have the issue of actually supplying enough ammo for the guns. As it stands Britain does not make 75mm guns or ammo. Yes it can set up production but that is not a quick or easy task. Britain can't rely on sourcing everything from America at this stage of the war. The cost will be enormous if they can get around the neutrality act and shipping things from America to Britain to then get sorted and put on a different ship to go to wherever Britain is fighting is a massive hassle and one that Britain would like to avoid if it could. Yes once Lend Lease starts that eases the problems and once America enters the war they mostly go away but that is making decisions with foresight that does not exist. Also relying on captured German stock to supply your guns is not a way to fight a war. If you can go it then it is nice but not something to rely on.
The million shells delivered for the 75mm guns was mentioned, so there wasn't any particular need to open a new ammunition production line for them.
Finally we have the issue of actually building more Guns. As I have already argued the likelihood of getting the 75mm of the RA is likely to prove difficult. In addition to that we have the cost and time of modifying them. If this was an option Britain wanted to seriously look at they would need to build the guns themselves. Again you cant rely on America until Lend Lease and that is 9 months from being signed into law let alone becoming the war winning juggernaut it would eventually end up as. Any production in Britain would run into problems. Firstly who would make it? we have already had a post about how stretched Vickers is producing what is already adopted and working on the new 3" HV gun so they are likely out. Pretty much every other manufacturer would be in the same position. Secondly what do you make it with, all of Britain's production is set up for calibres other than 75mm and any that may be useful like the M1931 AA gun by Vickers is being co-opted for another purpose. Then you may have someone come up with the genius idea of boring out the 6pdr, its already cropped up in this thread. Can you imagine the reaction if you suggested, in 1940, that we are going to take barrels that could go towards making the fancy new 6pdr that can either go into tanks or be used as AT guns and instead we are going to bore them out so we can have a new CS gun. People won't be happy with that idea, again we need as much as we can get now, anything that disrupts short term production is a non starter for the time being.
I'm not suggesting that the OTL
QF 75mm is going to appear here any sooner than it did OTL, there was an interesting comment a couple of days ago about the capture of French shells and powder in Syria which contributed to the development of the the QF 75mm. I'm trying to lay the groundwork for a much better Close Support Gun, which, hopefully by the time we get to the Victor, probably late 1941 the British armoured doctrine will have gone from some CS tanks offering smoke shells, to most tanks being able, a wee bit like the Panzer IV, to have a good HE capability, while still able to take on something with 80-90mm armour.
@allanpcameron I am sorry if this post comes across as overly harsh or critical, that really is not my intention. The timeline you have written has been truly excellent, you have written something that is not only a good piece of literature but also a well researched (pom pom kerfuffle aside) and completely plausible alt history. I have enjoyed every post and much of the surrounding discussion. I just feel that with this post you are potentially swerving too far into the territory of wanking the TL. I could well be wrong, it may in part be because of my own frustrations surrounding the discussions of guns in this thread that are causing me to read too much into one post. We already have posters almost giving the British a 75mm gun with APDS and HEAT rounds whilst they are being bombed by the Luftwaffe. I understand you wanting to move the UK in the direction of a dual purpose gun earlier but I think (and am fully willing to admit I could be wrong on this) you are too concerned with it when what you have already done has not only sped up the process but made it inevitable. Again sorry if this comes across as harsh or judgemental, I truly don't mean it too.
Neither harsh, nor critical. Happy to have any feedback, and especially such well thought out and argued as yourself has contributed regularly. Anyone who has a look at all the weird and wonderful experimentation and British (built in a shed) armoured vehicles that appeared because of the threat of invasion (
Beaverette, I'm looking at you) will know that nothing was too outlandish to look at, most of which was never given any real production capacity (Standard Beaverette notwithstanding).
Getting to a Universal Tank with a dual purpose gun is a matter of trial and error, experimentation and frustration. Am I trying to skip a few steps (Covenanter, Centaur, Cavalier and Challenger)? Yes I am. The Valiant is a better Valentine. The Victor will be a better Cromwell. The Comet, well, we'll have to see.
Please don't apologise for trying to keep me honest!
Allan
en.wikipedia.org
