New Replacement For The 5.56mm And The 7.62 Short
Ordinance has the right idea, but the wrong cartridge. It looks like they’re trying to replace both the 5.56 and the 7.62 with the SOCOR 6.8mm. I think for a light, crew served weapon they should go back to the full 30.06 machine 38 super ammo gun and get rid of the .308 entirely.
In a previous discussion I indicated that the .257 would be a good replacement for the .223. I’ve been researching it further, and it looks like a 6mm (.243) “secant ogive” of 87 grains would give the best results. With a ballistic coefficient of about .400 its superior to the 62 grain 5.56, and still has decent velocity. As you might know, the flatter the trajectory, the easier it is to stay on target.
This bullet would still be effective to about 500 meters, which is to say very effective at 100-300 meters. And long range effective – as in full auto suppressive fire – out to maybe 1000 meters. The biggest concern with the 5.56mm is that it is not lethal out to the ranges that regular troops are able to target with proper training (et. al., did any of you qualify behind the grenade shed?)
A slightly heavier and larger diameter bullet would solve the problem without sacrificing sufficient velocity and therefore trajectory. If Ordinance foregoes politics and really try’s to do the right thing, I think they should come up with the same conclusion. The only other thing they need is to get rid of that stupid crimp in the middle of the cartridge. It was supposed to stop people from shooting street cartridges in the full auto M-16, but we all know how easy it is to modify.
This gives comparable powder volume to the 6.8, which doesn’t have the crimp either. The reason for the ball propellant was to save money, but in the context of a new cartridge, it makes sense to spend a little more on powder to save weight (along with retooling.)
The ballistics of the 7.62×51(.308) and the 30-06 are nearly identical, in military loads. Why change? Our 7.62 weapons can use ammo from any of our Allies. I don’t think any military uses 30-06 any longer. If they still have some of the old Browning MGs, they’ve been converted to 7.62.
I’m not knocking the 30-06. It’s a fine cartridge, I own four 30-06 rifles. An advantage of the 7.62 is it is shorter than the 30-06(7.62×63), that 1/2 inch means the action has 1 inch less to travel during firing. The shorter action weighs less.
Any Grunt will tell you, lighter is almost always is better.
I may be mistaken, but I believe the Mexican Army still uses the “Mendoza” which is chambered in 30-06 (7.63 X 63). It’s their own design, and I think used the best ideas from the BREN, and BAR for its operation.