stancrist said:

Environmental regulations made it necessary to develop a "green" bullet, and the Army took the opportunity to get improved performance.

If this is the case how comes that they used the non green M855 for training in the US and issued the green M855A1 only for troops deployed abroad for years?
This defeats the purpose of having a round that complies to national regulations.

stancrist said:

Can you cite any instances where having considerably different controls caused a significant problem in combat for UK troops?

I have not the time to trawl through endless web sources, Stan. However, one nugget of information comes to mind from dim and dusty memory  concerning the development of the SA80 family which casts some illumination on the issue. The two combat variants of the family are the L85 rifle (c. 20 inch barrel) and the L86 LSW (Light Support Weapon, with c. 25 inch barrel). Both variants have conventional selective fire, but at some point it was suggested to modify the L86 so that it fired from a closed bolt in semi-auto and from an open bolt in auto. It was argued that this would enable the L86 to maintain a higher practical rate of fire without overheating or risk of cook-offs (the same idea used for the FG 42 and Johnson automatic rifles discussed elsewhere), which could prove of significant value in intense combat.

The proposal was rejected by the Army because they did not want two similar weapons with different controls and handling, as that could cause confusion in combat. 

schnuersi said:

If this is the case how comes that they used the non green M855 for training in the US and issued the green M855A1 only for troops deployed abroad for years?

I have never seen any reports of M855A1 ever having been prohibited from use on outdoor ranges.

Due to overpenetration concerns, use of M855A1 in live fire shoot houses was stopped in early 2015.

Army Stops Use Of EPR Ammunition In Shoot Houses, Round Has Too Much Penetration -The Firearm Blog

autogun said:

I have not the time to trawl through endless web sources, Stan.

And I would not expect you to spend the time to trawl through endless web sources, Tony. 

I asked in case you happened to have such info readily available.

autogun said:

However, one nugget of information comes to mind from dim and dusty memory  concerning the development of the SA80 family which casts some illumination on the issue. The two combat variants of the family are the L85 rifle (c. 20 inch barrel) and the L86 LSW (Light Support Weapon, with c. 25 inch barrel). Both variants have conventional selective fire, but at some point it was suggested to modify the L86 so that it fired from a closed bolt in semi-auto and from an open bolt in auto.

The proposal was rejected by the Army because they did not want two similar weapons with different controls and handling, as that could cause confusion in combat.

Well, sure.  Having two variants of the same rifle -- each operating differently from the other -- would all but guarantee "confusion" in combat.

Because they had two, virtually identical weapons used in the squad, it made perfect sense for both to have the same controls and operation.

However, it is clear that two or more dissimilar weapons with different controls and handling can be used, without causing confusion in combat.

stancrist said:

Are you suggesting something like this?

Similar, but more akin to the NZ Squad, where they have 1x 7.62 LMG per squad + 1x 7.62 DMR per squad. In this case it would be having 1x 6.8 dmr and 1x 6.8 lmg, giving the rest of the squad lighter rifles so they can carry either more ammo or other weapons (AT / drone jammer, etc)

"Such a caliber mix is contrary to US Army history."

It's become the standard for US SF; they pair their 5.56 rifles with 7.62 LMG (not sure if 1 or 2) and sometimes also a 7.62 DMR. 

This is also their plan now with SOCOM's switch to 6.5C - 6.5C LMG + 6.5C DMR, but 5.56 URG-I upgraded M4's as rifles.

SF equipment / tactics / experience often filter down to influence the regular Army. Perhaps this will happen with 6.8 as well.

gatnerd said:

...more akin to the NZ Squad, where they have 1x 7.62 LMG per squad + 1x 7.62 DMR per squad. In this case it would be having 1x 6.8 dmr and 1x 6.8 lmg, giving the rest of the squad lighter rifles so they can carry either more ammo or other weapons (AT / drone jammer, etc)

"Such a caliber mix is contrary to US Army history."

It's become the standard for US SF; they pair their 5.56 rifles with 7.62 LMG (not sure if 1 or 2) and sometimes also a 7.62 DMR. 

This is also their plan now with SOCOM's switch to 6.5C - 6.5C LMG + 6.5C DMR, but 5.56 URG-I upgraded M4's as rifles.

SF equipment / tactics / experience often filter down to influence the regular Army. Perhaps this will happen with 6.8 as well.

Such a caliber mix may have become standard for SF, but that does not really mean anything.

Special forces have long used weapons that differ in type and/or caliber from the regular Army.

As for copying the NZ asymmetrical weapons mix, that is contrary to (post-M14) Army history.

Even the Army Rangers squad has each of its fire teams equipped with the same weapons mix.

Also, a 5.56/6.8 mix would be contrary to the reason (Level IV armor defeat) for adopting NGSW.

Have you seen anything from the Army which indicates they are considering such a 5.56/6.8 mix?

stancrist said:

Having two variants of the same rifle -- each operating differently from the other -- would all but guarantee "confusion" in combat. Because they had two, virtually identical weapons used in the squad, it made perfect sense for both to have the same controls and operation.

I think it depends on how similar (or dissimilar) the weapons and their controls are. In the context of a new rifle and cartridge being selected to be used alongside the existing weapons in the same squad, it would surely be better to have the basic controls the same. As the saying goes: "if anything can go wrong, it will", and that probably applies to military operations more than most areas of life. 

To go back to the start of this sub-thread, using the AUG (which has very different controls from the conventional AR-15 pattern) in 5.56mm and a different rifle in 7.62mm (or 6.8 mm) must increase the training requirement.

autogun said:

I think it depends on how similar (or dissimilar) the weapons and their controls are.

I think that's true.

autogun said:

In the context of a new rifle and cartridge being selected to be used alongside the existing weapons in the same squad, it would surely be better to have the basic controls the same.

To go back to the start of this sub-thread, using the AUG (which has very different controls from the conventional AR-15 pattern) in 5.56mm and a different rifle in 7.62mm (or 6.8 mm) must increase the training requirement.

It seems like it may increase the training requirement.

Question is, does it increase it enough to really matter?

The British use a 5.56mm bullpup and a 7.62mm AR-pattern DMR.

The Aussies use a 5.56mm bullpup and a 7.62mm AR-pattern DMR.

Has either army expressed concern about the training requirement?

stancrist said:

Has either army expressed concern about the training requirement?

I don't know - I've never asked. 

Relevant take on NGSW

YouTube

A Critical Analysis: The Sig XM5 (M7)in 6.8, the Army got it Wrong.

The Sig XM5, (M7) points of concern with the rifle, and why I think it will not work as a general issue fighting rifle. My predictions with regards to its ro...