“...Research shows that both rounds will “stay supersonic longer, have less wind drift and better terminal performance than 7.62 mm ammunition,” SOCOM officials said....”
What a crock of horse puckey. Maybe with 7.62 NATO ammunition already in the inventory, but any comparison to commercial-only .264 that doesn’t also include commercial 7.62/.308 is comparing apples to rutabagas. Either they’re incapable of thinking outside the box or they’re cherry-picking facts to fit their foregone conclusion.
Ballistic coefficient is the controlling over both maximizing efficiency and minimizing wind drift. The highest BC 7.62 round currently in the inventory is the M118, which uses a 175-gr SMK. The SMK has an ogive of just 7.0 calibers. There are .30-cal bullets on the market with ogive numbers more than twice that high, and with a G1 BC that’s 25% higher than the SMK’s. The comparison they’re making is like measuring the speed of a 3-year-old thoroughbred against a 15-year-old draft horse.
There could be lots of other sound reasons, like lighter ammunition, less recoil and lower per-round costs, but they’re blowing smoke up your skirt with tales of “stay supersonic longer” and “less wind drift.”
I have a vague idea what BC, ogive etc. means but never really studied them.
I do know that the original 30-06 was loaded with 220 grain bullet. Those old parallel sided round nosed fmj bullets would penetrate like crazy.
In modern boat tail, pointed, bullets, a 220 grain bullet would have exceptional range. The trouble with the .308 is the smaller powder space is made even smaller with that weight bullet.
On the other hand, the 6.5x55 plus several other early 6.5s were originally loaded with 160 grain round nose fmj bullets.
Loaded with a 139 grain bullet of high BC or whatever it is, it performs like a very heavy 30 caliber but with less recoil, etc. but it also does not take up case volume.
Same applies to a 6mm with a heavy for caliber low drag bullet.
Finally - a voice of reason. 7.62mm NATO is an excellent long distance caliber.
Don’t fix what isn’t broken.
Thank you. That’s exactly what I was thinking, but you said it much better than I could have.
Well, kinda sorta in a vague sense.
What really is going is the fact that one can find bullets in 6.5mm that have Bcs in the range of .7 G1,at about 147 grains ( Hornady ELd Match) and a cartridge ( a short action 308 based case) that pushes these bullets at decent velocities-2750 fps or so ( and the mil will jump them up a notch or two as well) compared to the 762/308 Win, you’d have to get near a 220-240 grain bullet and out of that small case, you can barely push such projectiles at much past 2000 fps... even the venerable 30/06 struggles to push such efficient bullets much past 2400 fps.
The realities of a smaller, more efficient round in terms of size, weight, materials needed (tangibles) as well as platform requirements ( the 30s would need barrels in the range of 26-32 inches, while the 6.5 can get there well within 26 inches, maybe a bit less) then you have rifle weight, blast recoil ( have you ever fired a wound up 30 cal with a 240 grain bullet?)
One would have to venture into the 300 Mag category to get similar external ballistics but would have a rifle that weighs about 13-15 lbs (M2010 Sniper Weapon system), has a round that weighs about 700 grains, or about 10 to a pound ( the 556 weighs about 190-200 grains) and generates a recoil impulse of nearly 30 ft/lbs ( granted, my 416 Rigby smacks me with about 58 ft/lbs).
So, there you have it- a stepping out 6.5 reaches out farther than any non-mag 30 cal, faster and with more terminal energy. Plus it is a dream to shoot.
The SOCOM folks learn well from the Precision shooting types- both Hi- power match as well as PRS/F-Class- learning how the great shooters get the edge they need to win against other world class marksman.
There is a reason the 6, 6.5 and 7mms rule the match, practical and tactical world, the 6.5 is the better choice in terms of performance and energy while minimizing the log load and the shooters comfort-ability to boot.
In fact, in the precision shooting world of paper and steel targets, the 30s are the exception, excepting the International Palma game ( 800-900-100-yards with a 308/762Nato spec chamber shooting 155 grain bullets). I assure you, the only reason shooters use that combination is because the Palma organization demands it.
A Palma rifle usually wears a 30-32 inch bbl to squeeze every last FPS out of stout charges of medium powder to get that 155 grn bullet to remain supersonic out to 1000yds....Rules is rules.
SOCOM can write their own, and I doubt the 762 nato is to be found in this chapter.