Section Infantry Weapons

Contains threads on British Army equipment of the past, present and future.
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mrclark303
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Re: Section Infantry Weapons

Post by mrclark303 »

RunningStrong wrote: 21 Jan 2023, 18:43
mrclark303 wrote: 21 Jan 2023, 18:33 Snap..... Lots of experience with both calibers, we will have to agree to disagree.
You disagree with the US department for defence and army technical manual, both quoted at stating effective range of 602 yards in a 20" barrel.
It depends what you referring to by effective range, do you mean accurate placed shots, or suppressive fire?

As previously discussed, in ideal still conditions, 600 meters of accurate fire is quite possible with the right rifle.
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Re: Section Infantry Weapons

Post by Foxtrott_4 »

Alright, since i have found no answer to this anywhere else:
Does anybody know what ACOG or more specifically what reticle was used on the L85 A2 TES (first itteration)? I know That it was a TA31 since it featured the fibre optics and it was a 4x magnification and reticle was red but what style was it? Crosshair? Chevron? Chevron with stadia lines to either side?
Can anybody who has used that setup help me out here?

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Tempest414
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Re: Section Infantry Weapons

Post by Tempest414 »

Are taking about the Susat sight fitted to L85 ? if so it has a Obelisk coming up from the bottom of the sight picture

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Re: Section Infantry Weapons

Post by mr.fred »

Tempest414 wrote: 13 Feb 2023, 08:07 Are taking about the Susat sight fitted to L85 ? if so it has a Obelisk coming up from the bottom of the sight picture
No, he’s asking about the ACOG fitted to the L85A2, after the SUSAT and before the LDS.

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Re: Section Infantry Weapons

Post by Tempest414 »

mr.fred wrote: 13 Feb 2023, 11:01
Tempest414 wrote: 13 Feb 2023, 08:07 Are taking about the Susat sight fitted to L85 ? if so it has a Obelisk coming up from the bottom of the sight picture
No, he’s asking about the ACOG fitted to the L85A2, after the SUSAT and before the LDS.
Was that not a T coming from the bottom

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Re: Section Infantry Weapons

Post by Foxtrott_4 »

Tempest414 wrote: 13 Feb 2023, 08:07 Are taking about the Susat sight fitted to L85 ? if so it has a Obelisk coming up from the bottom of the sight picture
The SUSAT only has one reticle and its well known. I was Asking about the Acog that came before the Elcan specter

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Re: Section Infantry Weapons

Post by Little J »

I thought I had the model number written in a book somewhere, but I can't find it.

I believe it's the same one as the USMC use.

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Re: Section Infantry Weapons

Post by Ron5 »

Foxtrott_4 wrote: 13 Feb 2023, 19:13
Tempest414 wrote: 13 Feb 2023, 08:07 Are taking about the Susat sight fitted to L85 ? if so it has a Obelisk coming up from the bottom of the sight picture
The SUSAT only has one reticle and its well known. I was Asking about the Acog that came before the Elcan specter
Ask on AARSE

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Re: Section Infantry Weapons

Post by Foxtrott_4 »

Little J wrote: 13 Feb 2023, 20:28 I thought I had the model number written in a book somewhere, but I can't find it.

I believe it's the same one as the USMC use.
There are two versions of that acog. One is the TA31 RCO and the other one the TA31 RCO-M855. I think the latter one is fairly new. If it has a chevron reticle then its the first.

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Re: Section Infantry Weapons

Post by leonard »

In the meantime even the sailors in the Marine Nationale are starting to becoming a full HK416F rifle club member !!!!

Little J
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Re: Section Infantry Weapons

Post by Little J »

Interesting view point on the M-7 rifle...
https://www.armytimes.com/opinion/comme ... s-program/

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Re: Section Infantry Weapons

Post by Lord Jim »

Poiuytrewq wrote: 21 Jan 2023, 11:44
mrclark303 wrote: 21 Jan 2023, 11:19 Why indeed, it's 6.8 because that's what Uncle Sam selected, it's that simple really....
The difference isn’t enough to worry about but the 6.5 is inherently more accurate and would penetrate better with the increased sectional density.

IMO the 338 Norma magnum would have been the perfect replacement for the 7.62x51. It occupies a sweet spot between range, accuracy and retained energy at beyond 1000m.

Ballistically the 6.5 Grendel is also a ‘Goldilocks’ option but the case dimensions are suboptimal for sustained firing through automatic weapons. Effectively it’s too short and fat with insufficient body taper and the shoulder angle is also too aggressive.

Supersizing the 5.56 case to equal the Grendel case capacity and necking it up to 6.5 is an obvious solution but why would anyone want to do something so simple and straightforward?
There are currently two Light Machine Guns that use the .336 Norma Magnum Cartridge being tested in the field by US Special Forces. Light that 7.62/51 M240 but with firepower almost equal to .50 cal M2 Browning HB. Something I am sure our Special Forces will be keeping a close look at moving forward and an ideal replacement for the L7A3 and M2 Browning. Regarding RWS you can mount both a .338 LMG and 40mm AGL together on a number of Light Mounts. Would be god for Boxer.

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Re: Section Infantry Weapons

Post by NickC »

FWIW US Army FY24 budget released this week asking for $328 million for the NGSW, 17,122 -R/M5 assault rifles , 1,419 -AR/M250 belt fed light machine guns and 14,932 -FC / Fire control sight, (scope/laser/computer etc) .

My personal opinion is that when General Mark A. Milley, Chairman of the US Joint Chiefs of Staff retires, the main backer of the NGSW, it will limp along, don't see the M5 replacing the M4 wholescale, though do like the look of the M250, the more open is the question to me is whether US Army will change over from 7.62 to 6.8 and fund the cost of replacing all its 7.62 machine guns with 6.8 barrels, if they do expect British Army would follow.

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Re: Section Infantry Weapons

Post by Poiuytrewq »

NickC wrote: 17 Mar 2023, 11:02 ….US Army will change over from 7.62 to 6.8 and fund the cost of replacing all its 7.62 machine guns with 6.8 barrels, if they do expect British Army would follow.
Why would you want to do that?

What advantages has the 6.8X51 got over the 7.62X51 in the GPMG or Minigun?

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Re: Section Infantry Weapons

Post by NickC »

Poiuytrewq wrote: 17 Mar 2023, 11:12
NickC wrote: 17 Mar 2023, 11:02 ….US Army will change over from 7.62 to 6.8 and fund the cost of replacing all its 7.62 machine guns with 6.8 barrels, if they do expect British Army would follow.
Why would you want to do that?

What advantages has the 6.8X51 got over the 7.62X51 in the GPMG or Minigun?
Better ballistics and compatibility

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Re: Section Infantry Weapons

Post by mrclark303 »

NickC wrote: 17 Mar 2023, 11:47
Poiuytrewq wrote: 17 Mar 2023, 11:12
NickC wrote: 17 Mar 2023, 11:02 ….US Army will change over from 7.62 to 6.8 and fund the cost of replacing all its 7.62 machine guns with 6.8 barrels, if they do expect British Army would follow.
Why would you want to do that?

What advantages has the 6.8X51 got over the 7.62X51 in the GPMG or Minigun?
Better ballistics and compatibility
Sig have developed a section Light machine gun to go with the new rifle.

It's just not possible to rebarrel the GPMG, the chamber pressure of the new 6.8x51mm round is simply to hot for the piece to handle.

I too fully expect the UK to follow suit with its next rifle chambered in the new calibre.

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Re: Section Infantry Weapons

Post by Poiuytrewq »

NickC wrote: 17 Mar 2023, 11:47
Better ballistics and compatibility
Please elaborate?

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Re: Section Infantry Weapons

Post by NickC »

Poiuytrewq wrote: 17 Mar 2023, 12:32
NickC wrote: 17 Mar 2023, 11:47
Better ballistics and compatibility
Please elaborate?
Bullet ballistic coefficients.

My understanding the 6.8 will use a 140 gr bullet whereas the 7.62 L44A1 uses a 144 gr bullet, the cartridge case used exactly same and so same powder capacity.
(US Army specified special cartridge case for the 6.8 with stainless steel head to take higher pressure of ~ 80,000 psi with hotter powder for higher fps above standard brass case max of ~60,000 psi, though as far as know only the brass cased 6.8 is in production at the US Army Lake City arsenal).

Have no BC figures for the 140gr 6.8 (277) and 144gr 7.62 (308) bullets, have shown BC figures for a Sierra Matchking bullets below, first a 135 gr .277 (6.8) and second for a 150 gr .308 (7.62). The heavier 6.8 /140 gr bullet would slightly improve its BC whilst the lighter 7.62 /144 gr bullet would slightly degrade the .308 figures shown further widening the BC gap between the two different bullets.

.277/6.8 135 gr
Ballistic Coefficients and Velocity Ranges .488 @ 2800 fps and above .482 between 2800 and 2000 fps .440 between 2000 and 1500 fps .390 @ 1500 fps and below

308/7.62 150 gr
Ballistic Coefficients and Velocity Ranges .417 @ 2800 fps and above .397 between 2800 and 1800 fps .355 @ 1800 fps and below

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Re: Section Infantry Weapons

Post by Poiuytrewq »

NickC wrote: 17 Mar 2023, 14:25
Poiuytrewq wrote: 17 Mar 2023, 12:32
NickC wrote: 17 Mar 2023, 11:47
Better ballistics and compatibility
Please elaborate?
Bullet ballistic coefficients.
Thanks.

Firstly, don’t get too wrapped up in BCs. They are an important factor but not the only one. You also have consider muzzle velocity, recoil, chamber pressure, inherent accuracy plus how much kinetic energy the round puts on target and effectiveness at penetrating body armour etc.

Secondly, is it single shot, mag fed or belt fed. This is massively important. Generally cartridges with high chamber pressures and muzzle velocities are not ideally suited to belt fed or being fired on full auto for long periods. Just increasing chamber pressure and muzzle velocity doesn’t always make it better.

Chromium plating the barrel will help but all that heat in the throat will crack and erode the barrel steel much faster in the 6.8mm than the 7.62. In real terms that means changing the barrel more often or losing accuracy faster.

From a ballistic point of view the 6.8mm is a poor choice when compared to the 6.5mm or 7mm and in a practical sense I really don’t think it would make a decisive difference in the real world.

Of all the British Army’s priorities at the moment, this isn’t it.

However increasing the 5.56 up to 6mm or 6.5mm and replacing the 7.62 with the 8.6 would make complete sense but it really isn’t a NATO priority IMO.

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Re: Section Infantry Weapons

Post by Little J »

From what I understand, the full power 6.8 rips through barrels. May want to consider that before wholesale replacement

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Re: Section Infantry Weapons

Post by NickC »

Poiuytrewq wrote: 17 Mar 2023, 16:00
NickC wrote: 17 Mar 2023, 14:25
Poiuytrewq wrote: 17 Mar 2023, 12:32
NickC wrote: 17 Mar 2023, 11:47
Better ballistics and compatibility
Please elaborate?
Bullet ballistic coefficients.
Thanks.

Firstly, don’t get too wrapped up in BCs. They are an important factor but not the only one. You also have consider muzzle velocity, recoil, chamber pressure, inherent accuracy plus how much kinetic energy the round puts on target and effectiveness at penetrating body armour etc.

Secondly, is it single shot, mag fed or belt fed. This is massively important. Generally cartridges with high chamber pressures and muzzle velocities are not ideally suited to belt fed or being fired on full auto for long periods. Just increasing chamber pressure and muzzle velocity doesn’t always make it better.

Chromium plating the barrel will help but all that heat in the throat will crack and erode the barrel steel much faster in the 6.8mm than the 7.62. In real terms that means changing the barrel more often or losing accuracy faster.

From a ballistic point of view the 6.8mm is a poor choice when compared to the 6.5mm or 7mm and in a practical sense I really don’t think it would make a decisive difference in the real world.

Of all the British Army’s priorities at the moment, this isn’t it.

However increasing the 5.56 up to 6mm or 6.5mm and replacing the 7.62 with the 8.6 would make complete sense but it really isn’t a NATO priority IMO.
Would agree in general with your comments, but would add one major additional attribute for ammo which you did not include was weight, for an assault rifle light weight is essential so the infantry can carry enough rounds for max firepower in a fire fight, 30 round 5.56 magazines compared to only 20 round 6.8 magazine and why to me M5/6.8 combination fails compared to 5.56 assault rifles, understand 5.56 is not the best but it is lightweight and a fait accompli.

To me the biggest step forward highlighted in the NGSW trials was the True Velocity lightweight polymer ammo and yet was not adopted due to the criteria for the trials weighted on the rifles, the guns and ammo should have been assessed individually.

A minor point is the better BC for roughly similar weight bullet will give higher kinetic energy, range and flatter trajectory. That's the reason why prefer the 6.8 to the 7.62, though must say would not adopt the very high pressure US Army round for the belt fed machine guns with its expensive stainless steel head, as mentioned it would burn out the barrels at a much quicker rate and increase wear and tear on the guns, would stick with standard brass cased rounds and in perfect world move to lightweight polymer cases, saving weight always a big plus.

An American veterans view


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Re: Section Infantry Weapons

Post by mrclark303 »

NickC wrote: 18 Mar 2023, 10:41
Poiuytrewq wrote: 17 Mar 2023, 16:00
NickC wrote: 17 Mar 2023, 14:25
Poiuytrewq wrote: 17 Mar 2023, 12:32
NickC wrote: 17 Mar 2023, 11:47
Better ballistics and compatibility
Please elaborate?
Bullet ballistic coefficients.
Thanks.

Firstly, don’t get too wrapped up in BCs. They are an important factor but not the only one. You also have consider muzzle velocity, recoil, chamber pressure, inherent accuracy plus how much kinetic energy the round puts on target and effectiveness at penetrating body armour etc.

Secondly, is it single shot, mag fed or belt fed. This is massively important. Generally cartridges with high chamber pressures and muzzle velocities are not ideally suited to belt fed or being fired on full auto for long periods. Just increasing chamber pressure and muzzle velocity doesn’t always make it better.

Chromium plating the barrel will help but all that heat in the throat will crack and erode the barrel steel much faster in the 6.8mm than the 7.62. In real terms that means changing the barrel more often or losing accuracy faster.

From a ballistic point of view the 6.8mm is a poor choice when compared to the 6.5mm or 7mm and in a practical sense I really don’t think it would make a decisive difference in the real world.

Of all the British Army’s priorities at the moment, this isn’t it.

However increasing the 5.56 up to 6mm or 6.5mm and replacing the 7.62 with the 8.6 would make complete sense but it really isn’t a NATO priority IMO.
Would agree in general with your comments, but would add one major additional attribute for ammo which you did not include was weight, for an assault rifle light weight is essential so the infantry can carry enough rounds for max firepower in a fire fight, 30 round 5.56 magazines compared to only 20 round 6.8 magazine and why to me M5/6.8 combination fails compared to 5.56 assault rifles, understand 5.56 is not the best but it is lightweight and a fait accompli.

To me the biggest step forward highlighted in the NGSW trials was the True Velocity lightweight polymer ammo and yet was not adopted due to the criteria for the trials weighted on the rifles, the guns and ammo should have been assessed individually.

A minor point is the better BC for roughly similar weight bullet will give higher kinetic energy, range and flatter trajectory. That's the reason why prefer the 6.8 to the 7.62, though must say would not adopt the very high pressure US Army round for the belt fed machine guns with its expensive stainless steel head, as mentioned it would burn out the barrels at a much quicker rate and increase wear and tear on the guns, would stick with standard brass cased rounds and in perfect world move to lightweight polymer cases, saving weight always a big plus.

An American veterans view

The simple fact is Uncle Sam is the NATO piper and we all follow the piper....

6.8 X 51mm has been adopted and we all will eventually follow suit....

That said 5.56mm is to continue as a secondary calibre for decades to come in US service, so there's no crashing need to change..

I think the UK will be a relatively early adopter, as we are approaching the end of the road with the L85....

We will need to be looking at a replacement across the board by the early 2030's ( Colt Canada currently fill the gap with its limited issue standard rifles).

It won't necessarily be the Sig offering, all the major manufacturers are scrambling to re-design ( or design new) Rifles to use 6.8mm.

It will be an off the shelf purchase though, of that I am sure.

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Re: Section Infantry Weapons

Post by Poiuytrewq »

mrclark303 wrote: 18 Mar 2023, 11:31 6.8 X 51mm has been adopted and we all will eventually follow suit....
It will be interesting to see if that actually happens or if an intermediate round is also selected.

IMO the 6.8X51 is too much and not enough.
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Re: Section Infantry Weapons

Post by mrclark303 »

Poiuytrewq wrote: 18 Mar 2023, 12:23
mrclark303 wrote: 18 Mar 2023, 11:31 6.8 X 51mm has been adopted and we all will eventually follow suit....
It will be interesting to see if that actually happens or if an intermediate round is also selected.

IMO the 6.8X51 is too much and not enough.
I'm assuming not, I think 5.56mm will remain the alternative round, rather than adopt a new secondary round.

The Americans have effectively done a180 degree turn re the calibre and given us the grandson of .30-06!

The Americans intend to retain the M4 as a secondary weapon for crews, rear echelon sorts etc.

The UK, with its smaller armed forces will have a requirement for about 150,000 new rifles in the 2030's, it will be very interesting to see what 6.8x51 option becomes available from our 'go to' supplier Colt Canada in the next few years.
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Re: Section Infantry Weapons

Post by Little J »

mrclark303 wrote: 18 Mar 2023, 11:31 The simple fact is Uncle Sam is the NATO piper and we all follow the piper....

6.8 X 51mm has been adopted and we all will eventually follow suit....
And how many of those NATO countries will remember the US 762 / M14 bs and think "nah, lets wait a while and see it get dumped to a DMR role"?

As an aside... The M5 got rebranded the M7, for anyone that missed it

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