Section Infantry Weapons

Contains threads on British Army equipment of the past, present and future.
Tony Williams
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Re: Section infantry weapons

Post by Tony Williams »

mr.fred wrote: It does raise the possibility of buying a weapon in NATO standard but being able to run experiments with alternative calibres like Tony William's (and other's) General Purpose Cartridge. If you an run with 7.62mm and 5.56mm then you can run most things in-between.
Yes. The advantage of most 7.62mm weapons is that they can be converted to anything smaller, saving the cost of buying new guns.

marktigger
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Re: Section infantry weapons

Post by marktigger »

The Swede's have the FN MAG (GPMG) in 6.5mm x55

they also modified them slightly

Image

not exactly a fetching shade of green

But similar concept to the Minimi 7.62, But the interchange able MK3 is an interesting development. Can it be used in the SF role?

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Re: Section infantry weapons

Post by marktigger »

I find the mention of "intermediate" rifle cartridges as interesting a 7.62x51 is an intermediate cartridge and was designed to be so.

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Gabriele
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Re: Section infantry weapons

Post by Gabriele »

Intermediate rounds will only be selected if the US Army goes for one. Until the US Army does not move, the British Army won't, either.
You might also know me as Liger30, from that great forum than MP.net was.

Arma Pacis Fulcra.
Si Vis Pacem, Para Bellum

marktigger
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Re: Section infantry weapons

Post by marktigger »

Gabriele wrote:Intermediate rounds will only be selected if the US Army goes for one. Until the US Army does not move, the British Army won't, either.
Just like with 7.62x 51mm & 5.56x45mm as opposed to 7x43mm and 4.85x49mm had we gone British

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Re: Section infantry weapons

Post by Tony Williams »

marktigger wrote:I find the mention of "intermediate" rifle cartridges as interesting a 7.62x51 is an intermediate cartridge and was designed to be so.
"Intermediate" means whatever you want it to mean. It has also been used to describe 5.56x45 (intermediate in power between 7.62x51 and 9x19). In this context, it means roughly midway in size and power between 5.56x45 and 7.62x51 (but with better-shaped bullets so that it can match 7.62x51 in long-range ballistics). I usually refer to it just as the GPC nowadays (general purpose cartridge).

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Re: Section infantry weapons

Post by Tony Williams »

Gabriele wrote:Intermediate rounds will only be selected if the US Army goes for one. Until the US Army does not move, the British Army won't, either.
Absolutely.

Interestingly, various parts of the US Army (ARDEC, AMU and also funding for a Textron study) have carried out research into the optimum squad rifle/MG cartridge over the past few years, and they keep coming up with around 6.5mm calibre.

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Re: Section infantry weapons

Post by Tony Williams »

marktigger wrote: Just like with 7.62x 51mm & 5.56x45mm as opposed to 7x43mm and 4.85x49mm had we gone British
Depends on how you look at it. The 7x43 was designed to meet US long-range requirements which the British thought were unnecessary. Before then, a lot of work had been done by the British Small Arms Calibre Panel (popularly known as the Beeching report - yep, the railway assassin) and they had settled on a .270 calibre (6.8mm) round as optimal.

The photo below shows a selection of cartridges for comparison purposes, from left to right: .276 Pedersen (came very close to US adoption in the 1930s, the UK was very interested in it); .270 British (late 1940s); 7x43 British (.280/30); 7.62x51 NATO; 7x46 UIAC (current private US experimental); 6.5mm Grendel (current US commercial).

Image

The 4.85mm British was designed around the 5.56x45 and used the same case so that the two only needed a barrel change to switch between them - because the British realised that the 5.56x45 would almost certainly win the competition.

A few years before the 5.56x45 was selected by NATO, the British had carried out further research into small arms and decided that a 6.25 mm round would be optimal for infantry rifles. However, if we had chosen the .270 in 1950 we probably wouldn't have bothered with developing any smaller cartridge.

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Re: Section infantry weapons

Post by Little J »

Tony, been meaning to ask, have you got any experience with the 6.25? I've read that it had good potential but was dropped because the '77 trials spec'd 556 as an upper limit.

Did try designing my own "ideal" in .240 calibre reusing the 556 case, but think pressure would rip it to pieces, still if you know any wildcatters... :D
62 side.JPG
62.JPG
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mr.fred
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Re: Section infantry weapons

Post by mr.fred »

marktigger wrote: But the interchange able MK3 is an interesting development. Can it be used in the SF role?
You probably could, if you wanted, but I don't think it would hold up very well - it's essentially the same as the Mk48 that gets called the 'Maximi'

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Re: Section infantry weapons

Post by marktigger »

there was also the .280 Ross. But it is interesting that the optimal round seams to be around 6.5 to 7mm which the studies in the late 19th and early 20th C indicated as well.

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Re: Section infantry weapons

Post by Tony Williams »

Little J wrote:Tony, been meaning to ask, have you got any experience with the 6.25? I've read that it had good potential but was dropped because the '77 trials spec'd 556 as an upper limit.
The prototype 6.25mm as tested was just a necked-down 7x43, so had a very fat case for the calibre (same diameter as 7.62x51). This was to make it simple to convert 7mm EM2 rifles for testing purposes. Had the scheme been proceeded with, the intention was to develop a new, slimmer case but I don't think that ever got past the dummy stage. If you look at the photo on the front page of my website, the 6.25mm prototype is the sixth one along, the seventh is one of the dummy "final" rounds.
Did try designing my own "ideal" in .240 calibre reusing the 556 case, but think pressure would rip it to pieces, still if you know any wildcatters... :D
62 side.JPG
62.JPG
Well, there are various calibre production rounds based on the 5.56x45 case, from .20 (5mm) to .338 (8.6mm), and Cor-Bon makes a 6x45. Your case is better than Cor-Bon's for military purposes, because you have shortened it to allow the use of longer (heavier and better-shaped) bullets to boost long-range performance. I have no doubt that it would be more useful than the 5.56x45.

However, the key question to ask of any new rifle/MG round: is it capable of replacing the 7.62x51 as well as the 5.56x45? If not, then it's never going to happen, because the 5.56mm is regarded as adequate at shorter ranges, and the 7.62mm is there for anything longer. Which is why the 5.56x45 case is regarded as simply too small to provide the basis for any new infantry cartridge.

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Re: Section infantry weapons

Post by Tony Williams »

marktigger wrote:there was also the .280 Ross. But it is interesting that the optimal round seams to be around 6.5 to 7mm which the studies in the late 19th and early 20th C indicated as well.
It isn't just the calibre that matters: the .280 Ross is a powerful cartridge, almost in the Magnum class by modern standards, and not that different from the .276 Enfield which was developed as a replacement for the .303" in British service in the decade before WW1. These rounds were far too powerful, suffering from heavy recoil, lots of muzzle flash and blast, rapid heating and barrel wear. WW1 came along and caused the .276" project to be abandoned in favour of a new loading of the .303, to general relief all round I imagine.

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Re: Section infantry weapons

Post by marktigger »

yes was reading about the P13 trials scary. Have to say the Lee Enfield certainly redeemed itself in WW1 but I do pity the Canadians who had the Ross.

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Re: Section infantry weapons

Post by Little J »

Tony Williams wrote:However, the key question to ask of any new rifle/MG round: is it capable of replacing the 7.62x51 as well as the 5.56x45? If not, then it's never going to happen, because the 5.56mm is regarded as adequate at shorter ranges, and the 7.62mm is there for anything longer. Which is why the 5.56x45 case is regarded as simply too small to provide the basis for any new infantry cartridge.
Using things like Load From a Disc, Hornady Ballistics calculator, Powley computer and the velocity estimator from shootersnotes.com I came up with a 75 gr bullet (estimated at 0.41 ballistic Coefficient), muzzle energy of 1324 lb-ft. (same as 556), energy at 500 yards of 549 (close to a 6.8 spc) with recoil similar to 556 all with a 20 inch barrel. Even dropping down to a 12 inch you'd still get 443 lb-ft. @500... Theoretically.

The problem is it generates about 62,000 psi which would be on the limits of what the case could handle - I believe the new m855a1 has this level of pressure but its still higher than I'd like.

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Re: Section infantry weapons

Post by marktigger »

its what new devlopments in propellents and case design that will be the major governing factors. Caseless was meant to be the way ahead but it sank without trace. I suspect there won't be much in projectile design. It'll boil down to how tough we can make the weapon and the case

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Re: Section infantry weapons

Post by Tony Williams »

Little J wrote: Using things like Load From a Disc, Hornady Ballistics calculator, Powley computer and the velocity estimator from shootersnotes.com I came up with a 75 gr bullet (estimated at 0.41 ballistic Coefficient), muzzle energy of 1324 lb-ft. (same as 556), energy at 500 yards of 549 (close to a 6.8 spc) with recoil similar to 556 all with a 20 inch barrel.
It isn't just energy - since more than 99% of military bullets fired miss their targets (assuming they even have any in sight) it is clear that in practice the main effect of small arms fire is suppression. And to achieve that, the bigger the bullet, the better (other things being equal, as ever). This article contains the best analysis of suppression I've come across (among lots of other fascinating stuff), and should be essential reading for anyone interested in the effectiveness of small arms ammunition: http://quarryhs.co.uk/600mv2016.pdf

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Re: Section infantry weapons

Post by marktigger »

didn't Channel 4 many years ago do an analysis of cause of battlefield deaths in ww2 and its estimate of how many soldiers actually hit targets was very low I think in single figure percentages. The bulk of deaths were caused by Artillery and CAS something in the high 80%. (This is all from memory)

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Re: Section infantry weapons

Post by Tony Williams »

Ellis's Datebook on World War 2 gives the following percentages of battle wounds to British soldiers:

Mortar, grenade, bomb, shell: 75%
Bullet, anti-tank mine: 10%
Landmine, booby trap: 10%
Other 5%.

However, he also notes that there was great variation in the percentages attributed to bullet wounds in different theatres, with two divisional samples from NW Europe in 1944 giving 25.2 and 31.5%, at El Alamein (October 1942) 42.8%. A US SE Asia stat gives 38.4%.

Furthermore, these are casualties, not deaths. I discovered the following quote from another Ellis book on the web:
In both the Pacific and the Mediterranean it was found that of all those hit by bullets, 23 per cent were killed outright or died of their wounds. The equivalent figure for casualties from artillery fire was 19 per cent, from mortar fire 10 percent and from grenades 5 percent. Another sample of over 2,000 men hit made the same point, and also showed that although bullets were the greatest killer, 42 percent of men hit by machine-gun fire died of their wounds as against 26 percent of those hit by rifle fire.
I do wonder how they can distinguish between rifle and MG fire, but anyway it seems that bullets were a bigger killer than the headline stats indicate.

And of course, there is a further factor: the main value of small arms is in suppression - keeping the enemy pinned down so they can be finished off by artillery or mortars. If there were no small arms, the enemy could move much faster than artillery fire direction could keep up with.

So overall, no simple answer.

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Re: Section infantry weapons

Post by arfah »

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marktigger
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Re: Section infantry weapons

Post by marktigger »

tony in SEA campaign there was less artillery used and it was for the most part lighter than in western europe

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Re: Section infantry weapons

Post by Tony Williams »

arfah wrote:Considering that "99%" of shots "miss" we are probably better off with 5.56.

More rounds carried means additional chance for that magic "1%"
According to the analysis I provided a link to above, 7.62mm is twice as effective at suppression as 5.56mm, weight for weight (i.e. with only half the number of rounds).

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Re: Section infantry weapons

Post by Tinman »

Tony Williams wrote:
arfah wrote:Considering that "99%" of shots "miss" we are probably better off with 5.56.

More rounds carried means additional chance for that magic "1%"
According to the analysis I provided a link to above, 7.62mm is twice as effective at suppression as 5.56mm, weight for weight (i.e. with only half the number of rounds).
Have you ever been in a contact?

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Re: Section infantry weapons

Post by arfah »

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Re: Section infantry weapons

Post by Tinman »

arfah wrote:Who me?

Yep.
Not you!

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