question

rdt · Oct 17, 2011

what cartridge is a .308win necked down to hold a .277" (6.8mm) bullet? does not exist?

coop44 · Oct 17, 2011

quite possibly exists, but other than an academic exercise, why?

jer fly · Oct 17, 2011

Yeah nothing to gain over 260 rem, and 7mm/08. I do remember seeing a 308 necked down to 270 caliber in PO Ackley's book, but dont remember the verdict.

Jamie6.5 · Oct 18, 2011

It's called a .270 Redding and it's been around for ages.

rdt · Oct 18, 2011

cool, i was just curious. i was reading that one reason the m16 won out over the m14 was the ability to control the 5.56 in full auto/inability to control the 7.62. elsewhere i was reading about the 6.8spc: developed to improve ballistics but still fits in a standard ar15/m16. so my mind put the two concepts together. . .

except now im realizing you dont get the other great advantage of 5.56 over the 7.62: no great increase in ammo able to be carried.

im also thinking carry lots of ammo/ have fa control is what submachine guns are for?

deadshot2 · Oct 20, 2011

rdt said:
cool, i was just curious. i was reading that one reason the m16 won out over the m14 was the ability to control the 5.56 in full auto/inability to control the 7.62. elsewhere i was reading about the 6.8spc: developed to improve ballistics but still fits in a standard ar15/m16. so my mind put the two concepts together. . .

except now im realizing you dont get the other great advantage of 5.56 over the 7.62: no great increase in ammo able to be carried.

im also thinking carry lots of ammo/ have fa control is what submachine guns are for?

The weight of the ammo is a big consideration when you are supplying hundreds of thousands of troops. It may only be an ounce or so per cartridge but multiply that by the number of rounds you have to transport in a plane or helicopter.

Another reason that the M-16 was favored over the M-14 was that the "battlefield" was changing. No more engagements where your enemy was visible for up to 1,000 yards. Vietnam was a theater where your enemy was more likely engaged in the hundred yard range and rarely over 500 yards. Couple that with the ability to carry more ammo at the same weight favored the 5.56mm round.

Today we are back in a more wide open battlefield in Afghanistan which once again favors a long barreled 30 caliber rifle. The 6.8spc is another compromise. It's not as effective at long range as a .308 but it has more punch than the 5.56mm. It also offers the ability of he Military to convert in the field without having to send a bunch of weapons back to the Depot for conversion.

As for lots of ammo and FA, consider the fact that very few rounds actually hit targets other than by accident when spraying on FA. It's only good for making the other guy keep his head down so you can maneuver.

BTW, the reason the M-16 is more controllable over the M-14 on FA is the alignment of the barrel and stock. All recoil is straight back into the shooters shoulder. On an M-14 (AK-47 too), the stock is angled down so the bore is higher than the heel of the stock. This offset causes the weapon to rise when fired due to the angles involved.