I think the 6.8 will succeed, the ARMY has many reason to make sure it is adopted.
1. Politically, If they don't, the MARINES will be able to point to their M-27 which is the squad automatic rifle they have adopted to replace the M-249 in many rifle platoons and say to congress, see we were right all along. The MARINES had ordered a second tranche of M-27's that they were going to issue as their standard infantry rifle when the ARMY moved the M-250 along to derail the MARINES buying the M-27 and congress held up the MARINE order till the rifle/squad automatic weapon competition was over.
2. The ARMY let the manufacturers get creative. I said last year that SIG would win because the TEXTRON entry that used encapsulated ammo was a possible disaster waiting to happen in really hostile (environmentally hostile, not military hostile) places. The encapsulated ammo looks something like a plastic shotgun shell. It was a plastic tube filled with powder and a bullet inserted into the powder collumn. This type of ammo may have worked great, but I would worry about it in the hot middle east, tropical south east asia or russian winters.
I figured that the GENERAL DYNAMICS entry which used the TRUE VELOCITY ammo was not a problem from the environmental standpoint, but the rifle and squad automatic weapon were bullpup designs and the machine gun version used the same magazines as the rifle instead of a belt feed. That was not going to sell as a M-249 replacement.
Also, the bullpup design was the next big trend back in the 1980's with the BRITISH and FRENCH both adopting it and then the CHINESE doing it.
Well, the FRENCH have gone to the H&K 416 which is basis for the MARINES M-27 and is really just a piston driven version of the M-4.
The CHINESE have already started replacing their bullpup with an AR inspired design. The BRITS have been issueing M-4 carbines to the special units and had to pay the GERMAN'S to come in and fix there bullpup rifles as well.
SIG simply adapted their MCX line to the ARMY requirements. It was an already proven design. All those ergonomic features that everyone likes so much on the M-4 are their. No need for retraining how to load and swap magazines and if anyone is worried about the high pressure rounds, on a bullput, the round is right in front of your face or even under it.
3. In the NGSAW, the machine gun version, the army gets a weapon that can outrage the M-249 by about double the range, maybe more. They are talking about 1200 meters for the 6.8 instead of 300 to 400 for the M-249 or 800 meters for guns using the .308/7.62x51 NATO round.
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Also, both SIG and TRUE VELOCITY ammo could be used in weapons like the ARMY M-240L medium or general purpose machine gun and have longer range and a lighter ammo load.
The same goes for the M-134 MINI GUN that is mounted in so many ARMY helicopters and is also used around the world by the U.S. and other nations. All you need is a barrel change.
TRUE VELOCITY has been demostrating their ammo in otther guns and might be selected if the ARMY is disatified with the field perfomance of the SIG ammo. The SIG rifle and NGSAW could also be adopted to the TRUE VELOCITY ammo.
4.In a near pier war with the RUSSIANS or the CHINESE, our machine guns will outrange theirs. It will also outrange those machine guns using .308/7.62x51 or the RUSSIAN 7,62x54mmR. I was suprised that the .308/7.62x51 NATO round had not been replaced already by a 6.5 or 7mm round.
I would be less worried about RUSSIAN body armor than about CHINESE body armor. The RUSSIAN have made a mess of upgrading the systems they have like their tanks. They developed systems similar to the ISRAELI trophy active protection systems, but did not have the money to put them on their own tanks before sending tjhem into UKRAINE. They do offer the system on their export tanks, just on the ones in the RED ARMY.
The U.S. ARMY is putting the ISRAELI system on the M-1 ABRAMS tanks posted in GERMANY. This is a proven system and something it would seem obvious for the RUSSIAN'S to do when they are planning to invade someone.
The RUSSIAN simply do not have the money to fix their problems in anything like a world beating, top tier way.
Just my thoughts,
Jim
The rifle may be more problamatic. It is heavy compared to the M-4. It will add more weight, at least a pound and may be harder to shoot well. It will certainly recoil more than the .223/5.56x45 NATO round used in the M-4 carbines. The MARINES were planning to replace the M-4 with the M-27 (the H&K made, gas piston version of the M-4 like H&K 416) only with their special forces and infantry units. The artillery, logistics, mortar and other troops were going to stay with the M-4, so the ARMY may do the same.
Issue the M-5 to infantry, airborne, special forces and replace the .223/5.56mm M-249 in the squad automatic weapon role. They could just rebarrel the M-240, which is heavier and designed for more sustained fire role.
The 6.8 may well be a better machine gun round than the .308/7.62x51 NATO and that will probably decide its fate. As an infantry rifle, it may be too much of a good thing.
Jim