WI: 7.62x51mm never becomes NATO standard

According to Gun Jesus the British Army adopted the EM-2 as their official service Rifle until Churchill made them switch to the 7.62mm NATO round.
They adopted the EM2 as the No.9 rifle. But it never saw either mass issue or even mass production, before they decided to accept 7.62 NATO as the standard round and the L1A1 rifle as the new rifle. Said L1A1 being the "inch" pattern of the FN FAL
 
Seems like the supposed rimlock at Lee-Enfield is/was blown out of proportions, even with rounds purposly set to make rimlock happen? video
I'll reiterate that Bren worked just fine.
I own and regularly fire a No.4 rifle and never had a issue with rim lock. Now yes it can be a problem, but it's not nearly as much of one as it's made out to be.
Given how long Britain and especially Russia kept a rimmed cartridge in service it clearly isn't an insurmountable problem using rimmed ammo.
 
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Whilst rimlocks was not unknown in Lee Enfields they were rare if ever with properly trained soldiers who loaded their chargers correctly. The issue was exacerbated in popular experience by untrained civilian users and modern extensive use of old chargers. Chargers were never meant to be reloaded. They were disposable and were ejected from the rifle on closing the bolt. With new chargers as issued and the rounds loaded in the correct order the issue pretty well goes away. Some modern ammunition is also not made with proper specification rims. When used with the ammunition as issued for service in the period it was not an issue. Some of this applies to the Bren. In the period magazines were to be reloaded but magazines with issues (through damage or poor manufacture) were returned and fresh ones issued. We are using rifles more than 50 years old, sometimes over 100 years old, often with chargers of not disimilar ages which have been used scores more often at least than they were designed to and feeding ammunition not always well made for the use. Not surprisingly there are issues from time to time. Notwithstanding that rimless cases dispose of the issue entirely and is a better choice but being rimmed is not a barrier if you have to use it. Me, I would stick a better bullet on a Carcano case and fill it with better powder. Job done and home for tea and choosing a semi automatic rifle to use it. Controversially I would stick a (disposable) 10 round Mannlicher clip in it with top clip ejection but that is just me and not relevant to the OP. A FAL would be a sound choice.
 
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Given how long Britain and especially Russia kept a rimmed cartridge in service it clearly isn't an insurmountable problem using rimmed ammo.

Semi-rimmed ammo like the 6.5 Arisaka doesn't seem to have had the same sorts of issues as fully rimmed.

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Me, I would stick a better bullet on a Carcano case and fill it with better powder. Job done and home for tea and choosing a semi automatic rifle to use it. ...

Excellent points.
 

Deleted member 1487

A FAL would be a sound choice.
I'm surprised no one ran with the fully locked roller gas piston system post-war; by 1944 the Germans had perfected it and everyone had access to the work, but it was effectively ignored despite being lighter and more potentially accurate than the system the FAL used (or even that of a rotating bolt).

Edit: Apparently the Brits and US did both have designs using this, but sidelined them for more homegrown designs (Thorpe EM-1, which was insanely complex for no reason, and the US T-28 rifle).
 
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Deleted member 1487

BTW the AR-10 rifle has been made in 6.5mm now and works exceptionally well, with better performance than the .308 version.
Perhaps if something in 6.5mm is adopted as the NATO standard rifle/LMG-MMG round the AR-10 might not have had it's catastrophic barrel malfunction during testing and gotten a chance to edge out the M14 rifle in adoption. Gun Jesus recently did an M14 full auto shoot which shows how insane that rifle is to control in full auto, while having done previous AR-10 videos which shows it being much more controllable makes me wonder how it would have done with a lighter, lower pressure cartridge like most of the 6.5mm options in the 1950s. So if no 7.62 NATO perhaps an AR-10 US battle rifle instead of a M14? It would have done quite a bit better come Vietnam.
 
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BTW the AR-10 rifle has been made in 6.5mm now and works exceptionally well, with better performance than the .308 version.
Perhaps if something in 6.5mm is adopted as the NATO standard rifle/LMG-MMG round the AR-10 might not have had it's catastrophic barrel malfunction during testing and gotten a chance to edge out the M14 rifle in adoption. Gun Jesus recently did an M14 full auto shoot which shows how insane that rifle is to control in full auto, while having done previous AR-10 videos which shows it being much more controllable makes me wonder how it would have done with a lighter, lower pressure cartridge like most of the 6.5mm options in the 1950s. So if no 7.62 NATO perhaps an AR-10 US battle rifle instead of a M14? It would have done quite a bit better come Vietnam.

.243 Winchester came out in 1955. That's your 6mm round

ArmaLite AR-10 prototype was introduced for Army trials in late 1956

That said, I had an M1A, pretty much a civilian semi-auto M14, but in .243

It was a very fine setup, liked much better than the M14
 

Deleted member 1487

.243 Winchester came out in 1955. That's your 6mm round

ArmaLite AR-10 prototype was introduced for Army trials in late 1956
Looking at the particulars that might be a too hot for a 6mm barrel on semi-automatic or especially on full auto. Not fully Soviet 6x49mm Unified bad, but close.
https://en.wikipedia.org/wiki/.243_Winchester
75 gr (5 g) HP 3,447 ft/s (1,051 m/s) 1,979 ft⋅lbf (2,683 J)

https://www.thefirearmblog.com/blog...ll-power-calibers-019-russian-6x49mm-unified/
It fired a light bullet, just five grams (77gr), and had an incredibly high muzzle velocity of close to 1,150 m/s – that’s over 3,700 ft/s to the yanks reading this.
The 6x49mm was no intermediate cartridge, as it produced muzzle energies of close to 3,200 J.
Because of its heavy propellant charge relative to its small 6mm bore, the round produced incredible barrel wear to go along with its incredible ballistics. In machine guns, the zippy 6mm wore out barrels after just 5,000-6,000 rounds, about a third of the life span that could be expected from a 7.62mm barrel.

But there was someone who would support what the .243 Winchester had to offer:
http://www.g2mil.com/6mm_optimum_cartridge.htm
The Army had a logistically sound idea in trying to create a one-caliber, two-weapon, small arms system. Unfortunately, the wrong caliber was chosen, and a golden opportunity was lost. By insisting on developing the best 7.62mm cartridge, rather than the best possible cartridge, the logistical situation of today is at least as complex as it was in the 1940s, with the 5.56x45mm cartridge for use in the M16A2 rifle, M4 and M4A1 carbines, and M249 light machine gun, while the 7.62x51mm round is fired in the M21 and M24 sniper rifles, and the M60, M240B, and M240G medium machine guns.

One caliber can do it all. By sending a 100-grain, very low drag bullet downrange at over 2900 feet per second, the 6mm Optimum would provide snipers with the flat trajectory of the .300 Winchester Magnum. It would give machine gunners the penetration potential and tracer capability of 7.62 NATO, thereby permitting the development of an infantry machine gun that is light enough to replace both the 7.62mm medium machine gun and the 5.56mm squad automatic weapon. And, by virtue of being a compact, lightweight cartridge, with low recoil impulse, it should also allow the creation of a combat rifle that is little or no heavier than the M16A2.

The 6mm Optimum combines the best features of several existing cartridges into a compact, lightweight round that should be capable of all around performance unequaled by any other caliber. If the future brings about another quest for a single caliber common to the infantry rifle and machine gun, let the 6mm Optimum be the one for all!

https://en.wikipedia.org/wiki/.243_Winchester
105 gr (7 g) Amax BT 3,025 ft/s (922 m/s) 2,134 ft⋅lbf (2,893 J)
 
BTW the AR-10 rifle has been made in 6.5mm now and works exceptionally well, with better performance than the .308 version. Perhaps if something in 6.5mm is adopted as the NATO standard rifle/LMG-MMG round the AR-10 might not have had it's catastrophic barrel malfunction during testing and gotten a chance to edge out the M14 rifle in adoption. Gun Jesus recently did an M14 full auto shoot which shows how insane that rifle is to control in full auto, while having done previous AR-10 videos which shows it being much more controllable makes me wonder how it would have done with a lighter, lower pressure cartridge like most of the 6.5mm options in the 1950s. So if no 7.62 NATO perhaps an AR-10 US battle rifle instead of a M14? It would have done quite a bit better come Vietnam.

The composite barrel the AR-10 prototype was definitely not working for large cartridges, and I doubt it would have worked for almost any cartridge at the time. They barely work now with .223 and the ones on the market are extremely expensive. The AR-15 derivatives (with appropriate end-user support) probably did better than an sort of AR-10 would have, although an argument could probably be made that a heavier round would do better with vegetation. The big problem with the M14 was Ordnance Corps; both the AR-10 and the FAL have clearly proven themselves to be superior to the M14. With a history of willful negligence spanning a hundred and fifty years and tens of thousands of unnecessary American casualties, Ordnance had decided that the rifle the Army needed was a government-manufactured rifle designed for the 600 yard known distance range, not for anything soldiers were actually doing in combat, and they intentionally made the adoption of the M14's replacement (which they certainly had no hand in) as unnecessarily problematic as possible. The AR-15 was not adopted until Army field commanders went around Ordnance and straight to Congress and the NCA, which was why the AR-15 had to be adopted without proper testing. Even after the M16 was adopted, Ordnance couldn't keep their sticky little fingers out of the pie, which is why the ergonomically superior M16A1 was replaced with the M16A2, which had a longer stock, heavy barrel, and sights suited for the 600 yard known distance range and not combat.
 
Ordnance couldn't keep their sticky little fingers out of the pie, which is why the ergonomically superior M16A1 was replaced with the M16A2, which had a longer stock, heavy barrel, and sights suited for the 600 yard known distance range and not combat.

But the A2 were far more accurate than the A1 at shorter ranges too. And I liked the longer Stock.

The real fix would have been an earlier Scope on and A2, but the irons were good, as well as better magazines.
Something like the PMAG should have been done much sooner, the AUG showed it posible in the mid '70s, than deal with the crap aluminum and worthless mag follower in the GI Mag.
 

Deleted member 1487

The composite barrel the AR-10 prototype was definitely not working for large cartridges, and I doubt it would have worked for almost any cartridge at the time. They barely work now with .223 and the ones on the market are extremely expensive. The AR-15 derivatives (with appropriate end-user support) probably did better than an sort of AR-10 would have, although an argument could probably be made that a heavier round would do better with vegetation. The big problem with the M14 was Ordnance Corps; both the AR-10 and the FAL have clearly proven themselves to be superior to the M14. With a history of willful negligence spanning a hundred and fifty years and tens of thousands of unnecessary American casualties, Ordnance had decided that the rifle the Army needed was a government-manufactured rifle designed for the 600 yard known distance range, not for anything soldiers were actually doing in combat, and they intentionally made the adoption of the M14's replacement (which they certainly had no hand in) as unnecessarily problematic as possible. The AR-15 was not adopted until Army field commanders went around Ordnance and straight to Congress and the NCA, which was why the AR-15 had to be adopted without proper testing. Even after the M16 was adopted, Ordnance couldn't keep their sticky little fingers out of the pie, which is why the ergonomically superior M16A1 was replaced with the M16A2, which had a longer stock, heavy barrel, and sights suited for the 600 yard known distance range and not combat.
It certainly would have helped had they stuck to the steel barrel for the test as Stoner wanted, but was overruled by the president of Armalite. The Army testers did say the AR-10 was the best light rifle they had ever tested, so given that the big issue with it was that it was still technically just a prototype vs. the mature M14 design and the barrel burst issue (plus later problems with contracts they had in Latin America via rushing the production models) it sealed the fate of the design from the American perspective. I do wonder though without the missteps of the Armalite corp whether the AR-10 might have had a chance with a lighter caliber and no barrel burst, even with the Ordnance corps preferences.

Some guys did say that 243 was a barrel burner, but for all my Deer hunting, never went below 87 grains or faster than 3200fps

That's pretty much 6.5×55mm Swedish territory, not a barrel burner
The problem is running a larger caliber performance out of a smaller diameter barrel, it builds up heat a lot quicker and doesn't dissipate it as well.
Plus I bet you were doing single shots without quick follow ups. Military semi- and full-autos would be firing a lot more and putting more heat stress on the barrels. So you'd have to tone it down to performance like the 6x45mm SAW.

Edit: The 6mm Lee Navy cartridge is probably the sweet spot for post-WW2 rifles due to the less hot propellants and chroming of barrels; in it's time it was too hot for it's barrels.
https://en.wikipedia.org/wiki/6mm_Lee_Navy
100 gr (6 g) 2,680 ft/s (820 m/s) 1,595 ft⋅lbf (2,163 J)

So modernize the cartridge, which would including cutting it down substantially, and you're looking at a 1940s-50s 6x45mm SAW cartridge.
https://www.thefirearmblog.com/blog/2016/08/10/modern-intermediate-calibers-010-6mm-saw/
JX0mbc0.png
 
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The problem is running a larger caliber performance out of a smaller diameter barrel, it builds up heat a lot quicker and doesn't dissipate it as well.
Plus I bet you were doing single shots without quick follow ups. Military semi- and full-autos would be firing a lot more and putting more heat stress on the barrels. So you'd have to tone it down to performance like the 6x45mm SAW.

Anytime continuous rapid fire is planned for, QD barrels should be part of the mix. And if multiple mag dumps are needed, burned out barrels is a lesser concern, especially when the AR series- it's no big deal, unlike the M14
 
Edit: The 6mm Lee Navy cartridge is probably the sweet spot for post-WW2 rifles due to the less hot propellants and chroming of barrels; in it's time it was too hot for it's barrels.
https://en.wikipedia.org/wiki/6mm_Lee_Navy
So modernize the cartridge, which would including cutting it down substantially, and you're looking at a 1940s-50s 6x45mm SAW cartridge.

And we are back to the Savage 250-3000 of 1915, 6.5x49mm

75 gr (5 g) HP 3,170 ft/s (970 m/s) 1,674 ft⋅lbf (2,270 J)
90 gr (6 g) HPBT 2,997 ft/s (913 m/s) 1,795 ft⋅lbf (2,434 J)
100 gr (6 g) SP 2,864 ft/s (873 m/s) 1,822 ft⋅lbf (2,470 J)
117 gr (8 g) SBT 2,652 ft/s (808 m/s) 1,828 ft⋅lbf (2,478 J)
 

Deleted member 1487

And we are back to the Savage 250-3000 of 1915, 6.5x49mm

75 gr (5 g) HP 3,170 ft/s (970 m/s) 1,674 ft⋅lbf (2,270 J)
90 gr (6 g) HPBT 2,997 ft/s (913 m/s) 1,795 ft⋅lbf (2,434 J)
100 gr (6 g) SP 2,864 ft/s (873 m/s) 1,822 ft⋅lbf (2,470 J)
117 gr (8 g) SBT 2,652 ft/s (808 m/s) 1,828 ft⋅lbf (2,478 J)
Not necessarily, though it could be necked down to 6mm to get those numbers. The issue with using 6.5mm rounds that are that light is the aerodynamic forms are lower than the heavier rounds, which is an issue for US army demands for ranged performance. It should be noted that those numbers are out of a 24 inch barrel, not a 20 inch AR barrel.
Still, since it is out there might as well use it rather than developing something totally new
 

Deleted member 1487

The next question is whether adopting the AR-10 in 6.5 or 6mm as a reasonably high powered 800m round would head off the move to the 5.56 SCHV round/rifle, especially if the AR-10 performs well in the jungle conditions of Asia compared to the faulty M14s.
 
Rimmed ammunition in an automatic weapon is a pain to load to avoid misfeed. I have done on the Bren so I speak from experience!!!
———————————————————————————————

The opposite of poorly-trained, physically exhausted, emotionally exhausted after a week of shelling, paranoid after too many air strikes, malnourished, under-dressed, thirsty, soldiers huddling in the bottom of a muddy trench, in the dark, pelted by sleet, etc.
Rimmed cartridges are more difficult to feed with belts because they require two extractors. The first extractor pulls the cartridge - rear wards - out of the cloth belt. Something shifts it down to align it with the bore, the usual firing sequence, then a second extractor pulls the spent shell out of the chamber. Repeat until you run out of enemy.

OTOH rimless ammo only has to be pushed - forward - out of metal links.

Most of my MG experience has been on Browning M1919A4 and M2 .50 caliber. If I am going into a fight, I prefer to start with the .50 cal!
 
The next question is whether adopting the AR-10 in 6.5 or 6mm as a reasonably high powered 800m round would head off the move to the 5.56 SCHV round/rifle, especially if the AR-10 performs well in the jungle conditions of Asia compared to the faulty M14s.
i'm going to say no,
the first adopters of the ar15/m16 platform (the air force, army sf) will still appreciate the lighter carbine, and especially the lighter ammo
and i'll point out that the m1 carbine still became very popular in ww2 even with the m1 rifle being available, and that's analogues to the ar10-ar15 spilt
 

Deleted member 1487

i'm going to say no,
the first adopters of the ar15/m16 platform (the air force, army sf) will still appreciate the lighter carbine, and especially the lighter ammo
and i'll point out that the m1 carbine still became very popular in ww2 even with the m1 rifle being available, and that's analogues to the ar10-ar15 spilt
It was adopted by the Air Force, but resisted by the Army until the M14 failed badly in combat due to its construction and a basically flawed design as well as the insufficient production. That of course led to the very serious problems of the AR-15/M16 when it showed up in combat, worse issues than the M14 had and lasting for years.
With an AR-10 that is actually controllable in full auto due to a less powerful/smaller caliber cartridge, had the climate resistant non-wood construction, and could be made in sufficient numbers it is hard seeing the AR15 unseating it in army use. Given the historical reliability of the AR-10 in service in Africa with the Portuguese it probably would have been fine in Vietnam. At worst the AR-10 remains as a long range sniper weapon/DMR.
 
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