Steve Holland is a very interesting character. He was a Green Light Team 18E from back in the 1980s. He bypassed the normal commo section work that 18Es would do after SFQC at Group, before getting assigned to their ODAs, because they needed a commo guy on one of the Teams in the Green Light Company, which was a priority mission set in the Cold War. Green Light = HALO qualified ODAs that jumped-in the MK-54 SADM (nuke).
Anyway, he ended up in a senior NCO products development lead position in 5th Group, where he went around asking the end-users what it was that they wanted. At the time, there were no less than 3 different programs for small arms development specific to AR-15 carbines and rifles for SOF, pre-9/11.
1. The Special Purpose Receiver/Rifle. The SPR was focused on a Light Sniper System based on modifications to 723s and 727s within JSOC. Army JSOC Sniper Troops (former RRD, Ranger, SF, and LRS guys who had been to USMC SS Course, SOTIC, and/or Benning and Unit-internal Sniper Troop training) had the armorers build their 723 uppers into highly-accurate lightweight precision carbines with free-float tubes and optics, as well as the AIM-1 or PAQ-4C LAM, suppressed with Ops Inc cans, for close target Recce and precision fires support when over-watching for Assaulters. Imagine a Colt 723 with a 12.7” SR-25 fiberglass or Bushmaster V-Match aluminum free-float tube, a FSB pocket cut, rail sections attached for the LAM, Surefire, VFG, and provisions for bipod-mounting dependent on the mission profile, with an Ops Inc can sleeved under the handguard. I have yet to see any online photos of these, but the ones I’ve personally seen were well before the SPR program. The later ones had shaved uppers with Weaver/early 1913-type rails installed on them before/as the M4 upper went into production.
Dam Neck guys saw these Sniper Support carbines being used in The Unit by their Army counterparts during JFXs, and wanted their armorers to make the same thing for them. By the time Dam Neck started doing it, the M4 had just gone into production, so there are some photos of Dam Neck Assaulters with little free-float 727 carbines, and some with the longer barreled Sniper Support/Recce carbines like this:
SF SOTIC Committee guys at Range 37 saw these JSOC Sniper Carbines, and thought they would be good for SF and USASOC as well. The joint requests from Army SF and white-side NAVSPECWAR in the regular Teams led to Crane Indiana doing what we all came to know as the SPR, but its origins were really in The Unit/Army JSOC in the early 1990s.
2. The Enhanced Rifle Cartridge Program. There were other requests for an improved barrier defeat and CQB performance cartridge to fit inside the M16A2 Carbine (723 and 727) coming from the CQB Committees in both the Army and Navy, as well as unnamed entities with the ability to fund a program with Colt that dates back into the late 1980s. That resulted in Colt’s work on the Colt AR-15 in 7.62x39, which was later marketed to the civilian sector as the 7.62x39 Sporter. One of the ideas was to be able to use host nation supplies of common 7.62x39 ammunition but in the more familiar, compact Colt Carbine format used by some units in SF.
ECR divided into 3 camps. A) 7.62x39 UW Carbine, B) Improved terminal performance 5.56x45, and C) An entirely new Special Purpose Cartridge. Steve Holland at 5th Group Special Products Development and Chris Murray from the AMU began working on a new cartridge that would provide more momentum and terminal ballistics effects within 0-300m from carbines, since 7.62x39 suffered from magazine configuration issues in the AR-15 at the time. After testing with calibers ranging from 6mm to 30 cal in a shortened 30 Remington parent case, they settled on .277”/6.8mm as the bullet diameter to nail down and proceed with that could still fit inside the standard profile of a 30rd M16 STANG magazine and soldiers’ mag pouches. This became known as the 6.8x43 or 6.8 SPC. It was originally supposed to fit and function in existing magazines, but of course did not.
3. DMR rifle cartridge. As the momentum began to build within USASOC and SOCOM for their new Special Purpose Receiver/Rifle in the DMR role to augment the precision fires within small units where they used to use M21s, M14s, and the new SR-25s, they also needed a new accurate cartridge with better downrange retention of momentum. Within JSOC, they had been using 68gr and 69gr Match ammo loaded for them independent from the normal DoD acquisition channels in the early 1990s, along with a heavy diet of M855. The 75gr Hornady, 77gr Nosler and 77gr SMK (non cannelure) were seen as the most promising, highest BC projectile they could magazine-COL load, so in conjunction with the AMU and the private sector, the Mk.262 cartridge was born. Original 77gr SMK didn’t have a cannelure, while the 77gr Nosler did. USMC became very interested in the SPR program as well by the early 2000s, and spent significant resources funding their own testing before ordering over 1 millions rounds of it.
The 6.8x43 proponents tried to get it to also do the SPR/DMR role with the Murray DMR chamber, but the supersonic reach and wind drift was worse than 5.56, and 77gr SMK extended the supersonic reach farther, with less drop as a result. SOCOM and USMC also funded several different 5.56x45 cartridges that improved the terminal performance, and by the time the 6.8 ammunition went into production, the ECR and DMR requirements were already satisfied in 5.56x45 without having to make a caliber or magazine change within the operational units.
That’s how we got:
Mk.262 Mod 0
Mk.262 Mod 1
5.56 Optimized/Brown Tip Barnes TSX
Mk.318 Mod 0 SOST
And eventually
M855A1
I haven’t seen someone make a connection between 6.8x43 and 6.8x51 for projectile diameter demand baseline, but wouldn’t be surprised if it was influenced that way. The interesting thing is all the recently-retired US Army SOTIC and Navy SEAL Sniper guys have the same reaction to the NGSW, which is that it seems like a DMR, not something you would issue out to everyone due to weight, bulk, limited mag capacity and ammo carriage on soldier’s load.