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Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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The Foresight War Revisited: small arms   Novel: The Foresight War

Started 16-Feb by autogun; 7458 views.
Martin2515

From: Martin2515

17-Apr

SMG and Pistol in 9x19 is probably the best bet given the coming new cartridge. Keep the SMG as simple as possible except with the already mentioned double feed magazine so that they can be produced in massive quantities. Pistol, FN Browning hi-power, has the capacity you want whilst using the same round as your SMG. In addition it is nearly ready to go so no messing around, just grab it off shelf and have done. You only need it to simplify logistics when issuing pistol calibre rounds. 

A rifle round similar to .270 is a good starting pint but a couple of points. First a 6.5mm round likely gets better long range performance all other things being equal. Second the muzzle velocity was probably a bit high for true full auto controllability 2600ft/s to 2700ft/s is probably good enough. They are realistically nitpicks though, the real problem may well be the rifle. Going the FG42 type route is likely asking for trouble. The idea of a rifle/LMG cross weapon sounds good but adds complexity and cost, particularly if you want the open bolt full auto setting. Personally I think just going for a good quality pure assault rifle is a better bet, you likely get a less complicated and cheaper weapon. The LMG in the new calibre can be handled separately, even by a UK company if needed. As for the rifle layout a bullpup design is probably the best bet just because space is likely to be at a premium in any WW2 APC in particular though landing craft and planes can be tight as well. Not a hard requirement though. 

For AFV and aircraft machineguns just adopt the Browning 1919 in .30-06. Britain will end up getting lend lease tanks and planes using a version of the Browning in that calibre anyway so may as well standardise early for simplicity and logistics sake. 

For larger calibre weapons the .50 BMG is again the better path. Lets face it the .55 boys and .50 Vickers mix was less than ideal, might as well again go American early to simplify things down the line. It's not like you miss out on anything capability wise and realistically how much use is Britain going to be making of .50 calibre weapons anyway? The one thing I would say is keep the Boys going but give it the ability to fire HEAT grenades like the GrB 39 just in case you run into any issues with the PIAT/Carl Gustav. 

autogun

From: autogun

18-Apr

My thinking has evolved slightly since I proposed the .270. The problem with this is that it did not exist in the 1930s, so it would be necessary to begin the ammo design from scratch and complete that job before giving gun development contracts to ZB and FN. Instead, I have settled on the .276 Pedersen as this had been made in large quantities in the UK and was fully developed. It went through various design changes in the USA, but the original spec - a very well-shaped 125 grain bullet fired at 2,520 fps - is just about ideal for the purpose. 

I think that the "FG 42" type of gun would be ideal for the paratroopers, who may need to rely on whichever rifle they are carrying if they fail to retrieve any weapons containers. It would also be useful for other special forces who need to be able to generate heavy firepower from small numbers of troops. It would be a costly gun but the various elements of it are already known, so competent gun designers such as those in Belgium and Czechoslovakia shouldn't have any great problems is designing a good weapon. 

The next stage would see a simpler bullpup with a shorter and lighter barrel and without the open-bolt feature, using the same ammo and magazines (24 rounds, IMO). There would also be a  belt-fed LMG with a quick-change barrel: this combination of a long-range assault rifle and an LMG may be preferred by the regular army.

The .303 Browning would be my preferred choice of vehicle gun because it would already be in production for aircraft so it would be a matter of "de-tuning" it with a heavy barrel and half the rate of fire. The big advantage the .303 Browning has over the .30 (apart from the fact that the ammo is already being mass-produced) is that the guns were modified to fire from an open bolt to avoid cook-offs (cordite was more prone to that, apparently).

Like the Germans, I wouldn't bother with any .50 cal weapons: Oerlikons would do that job.

I think that two competing projects should be developed for the PIAT: a recoilless gun and a rocket launcher. May the best one win...

Krenske

From: Krenske

19-Apr

For man portable / Light AT, Have you considered both.

A shoulder fired rocket in the RPG 1/2 style, for a light weapon at low levels in the organisational structure (team of three should be able to carry 9+ rockets). These should be cheap, good for the entire war and range out to 150m.

A recoilless gun as a more general weapon at higher levels. This can be either a heavier, longer range weapon but still man portable or as a much more effective weapon but too heavy for real man portability. Effectively a 80-90mm weapon of 30kg and a 200-300m range or out to around 100 kg and a 1000m range against static targets. This seems to be where the two recoilless rifle types in the calibre sit, although there are outliers (Folgore for weight, German 75 for range).

The light weapon is supplemented by the heavier and more specialist weapon. But heavy is relative as the 80-90 mm RRs are still a lot lighter than a 57mm class pure AT gun at ~1100kg.

A benefit of following both development paths is if one fails the other can somewhat cover the gap. I would not think either could fail as both types were developed relatively quickly and successfully IRL.

PK

Wessels3

From: Wessels3

19-Apr

My thinking has evolved slightly since I proposed the .270. The problem with this is that it did not exist in the 1930s, so it would be necessary to begin the ammo design from scratch and complete that job before giving gun development contracts to ZB and FN. Instead, I have settled on the .276 Pedersen as this had been made in large quantities in the UK and was fully developed. It went through various design changes in the USA, but the original spec - a very well-shaped 125 grain bullet fired at 2,520 fps - is just about ideal for the purpose. 

The UK bought a large quantity of Japanese Arisaka rifles and carbines in 1914, and Kynoch produced the 6.5 x 50 SR ammunition. The simplest way for Britain to have developed an intermediate type cartridge, would have been to use an Arisaka carbine (19.2 inch barrel, and a very strong action) and develop a new cartridge around the 6.5x50 SR cartridge case. It would have been a simple matter to create a round firing a 120-130 grain projectile at 2500 fps from the Arisaka case and carbine combination. A Lyman handbook from the seventies shows numerous loads using a 129 grain spitzer bullet achieving in excess of 2500 fps, even over 2600 fps, from the Arisaka carbine, using all manner of IMR powders. 

The case could have been left in semi-rimmed configuration but preferable, and simple, would have been to modify it to a true rimless design.

autogun

From: autogun

19-Apr

Wessels3 said:

The UK bought a large quantity of Japanese Arisaka rifles and carbines in 1914, and Kynoch produced the 6.5 x 50 SR ammunition. The simplest way for Britain to have developed an intermediate type cartridge, would have been to use an Arisaka carbine (19.2 inch barrel, and a very strong action) and develop a new cartridge around the 6.5x50 SR cartridge case. It would have been a simple matter to create a round firing a 120-130 grain projectile at 2500 fps from the Arisaka case and carbine combination. A Lyman handbook from the seventies shows numerous loads using a 129 grain spitzer bullet achieving in excess of 2500 fps, even over 2600 fps, from the Arisaka carbine, using all manner of IMR powders. 

Yes, I have argued this case myself assuming slightly different circumstances - see https://quarryhs.co.uk/256brit.htm

The British bought around 150,000 Arisaka rifles and carbines, but by the end of WW2 had sent 128,000 of them to Russia; only 17,000 or so remained in British service, and probably not for long. Over 550,000,000 rounds of ammo were made (largely supplied to Russia, again) but in the form of the Type 30 loading with a round-nosed bullet. The Type 38 spitzer loading fired a 139 grain bullet at 2,500 fps.

In the TFW context, why develop a new version of an old cartridge instead of adopting a modern round which is fully developed with an excellent bullet, and was made in quantity by Kynoch only a couple of years before? 

QuintusO

From: QuintusO

20-Apr

I see you are continuing your vigilante crusade against the roving gangs of muzzle velocity who killed your parents.

In reply toRe: msg 76
Refleks

From: Refleks

9-May

I know this is a bit of a reach to suggest, but for Germany, what about shifting away from 9mm and pre-emptively adopting 7.62x25 Tok. From a manufacturing standpoint they were already set up to make 7.63x25 Mauser so it's not far off (.312 vs .309 diameter, and of course the differences in pressure) and if they focused on mass producing easy to manufacture clones of the PPSH-41 / PPS-43 starting in '35, they'd be available for the start of the war and they'd have an advantage later in being able to use captured Russian ammunition, and even magazines and guns far from home. They captured obscene amounts of artillery and ammunition during the initial invasion anyway, it would certainly see use.  The drums were some of the few that could be considered reliable, and the pattern for them was derived from the Finnish Suomi KP/-31 which were readily available in '35 to examine and produce.

The PPSH-41 in the Soviet Union got cheap enough that it was even cheaper and faster to produce than the bolt action rifles (142 rubles for the SMG vs 170 rubles for a Mosin Nagant), partially because they could use the same barrels (both had a 1:9.5 twist) and cut it in two for two SMGs.

Along those lines, to further consolidate production of ammunition they could neck the 7.9x57 down to 150gr 7.62 (0.312) and use the same bullet for both their GPMGs and an intermediate cartridge (7.62x41).  The intermediate cartridge can share the same base diameter of the 7.62x25 Tok cartridge and be used as the parent case for both cartridges from the manufacturing end*

I'm sure this isn't "optimized" as far as bullet weights and BC and all that, so it may be like blasphemy here, but it does their allow small arms manufacturing to use two bullets, and two parent cases (to make all three), for all the small arms, and it would simplify barrel production (since all three use the same twist rate) to further drive down costs.

*The reason I prefer this approach over simply a shortened 7.9x57 is that I'd also like to move the MG42s to the platoon and have the rifleman and automatic riflemen in the squads use the intermediate cartridge optimized for 300m, including a smaller belt fed SAW (could be a baby MG42, like Cetme Ameli). The smaller base diameter allows for potentially a 200 round box without being unmanageable (see M249) whereas the larger base diameter of something like 7.62x39 can only fit about 100 rounds in a similar footprint (see RPD) and 7.9x57 has an even larger base diameter than that which would just be worse.  So 7.62x41 ends up resembling a longer 300 blackout to offset the smaller case capacity versus the 7.62x39, and make room for the boat tail of the 150gr round.

____

As an aside, a 40mm grenade launcher along the lines of the RGM-40 Kastet would be a no-brainer and simple to produce once the high-low pressure concept is explained, and by making the low pressure chamber the launcher itself you don't have to worry about cartridge cases, which I find pretty elegant.

 

  • Edited 09 May 2021 7:28  by  Refleks
autogun

From: autogun

9-May

I think I need to remind you of the operating principle: "First, do no harm"!

There was nothing at all wrong with the 7.92x57 as a full-power round for use in long-range rifles and MGs. I would leave that entirely alone. The 9x19 was equally well established for pistols and SMGs (the 7.62mm Tok was a handful in a pistol). That leaves a requirement for something in between the 9x19 and the 7.92x57 for use in assault rifles. There is a fair amount of flexibility in the specification of the weapons and ammunition to meet this need, but nothing much wrong with the 7.92x33 which the Germans came up with. It just needed to be available several years earlier.

Refleks

From: Refleks

9-May

I admit I favor disruption early to desperation in design simplification later, but perhaps I am taking production rate considerations and ease of manufacturing to the extreme ;)

MG-42 and MP44 in '38 it is!

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