So, what exactly did US military gain by switching from 30-06 to .308?

[RX-79G]

.308 was the mistake that followed the mistake of .30-06. In the early '30s everyone already was saying what they're saying now with 6.8mm intermediate rounds. They were saying it again in the late '40s. The bass-ackwords US armory board is a fine example of a group that is completely unable to learn from history.

When 7.62x51 became standard, a couple of smart countries downloaded it to make it into an intermediate cartridge. That's why the Japanese Type 64 has a reputation as the best full auto 7.62 rifle. The Spanish did the same thing.

The US Armory board also destroyed one of the AR-15s best features - 1:14 rifling.

Germany was going to skip 5.56 altogether. The G3 worked well enough and they were going to skip to the next generation with the G11. But then reunification occurred, and the need and budget went away.

I like .308 - accurate and powerful enough. Glad I never had to carry one in combat, though. What a pain.

 

[HiBC]

The Garand IMO,is a good rifle.That said,the necessary pressure curve,op rod bending issues,etc limit how much of the 30-06 case capacity that can be used.
"Yeah,buts" aside,the Garand was the reality of the time.

Suitable Garand loads come in at around 46 to 47 gr of appropriate powder.

That much fits in a.308 case.Committee/drawing board thing.

A full BAR mag vs a full M-14 mag....Which is better?

 

[44 AMP]

A full BAR mag vs a full M-14 mag....Which is better?

That depends whether I'm aiming individual shots, or laying down suppressive fire. At half the weight of a BAR, the M14 is a lot nicer to carry. For full auto fire, I'll take the heavier gun.

 

[Model12Win]

They gained a smaller cartridge with nearly identical ballistics.

The 7.62x51mm cartridge is shorter and lighter than the 7.62x63mm (.30-06) cartridge that it replaced, but was just as powerful.

A rifleman/machine gunner could carry more 7.62mm NATO ammo for the same weight of .30-06 ammo. Also his weapons could be slightly more compact and lighter because the receiver could be made shorter for the shorter cartridge.

It was a win-win situation and it was good choice. The 7.62x51mm NATO is a great and extremely versatile round that serves our military and many other militaries very well.

 

[HiBC]

44AMP,agreed,the weapons are different.Agreed,for a full auto roll,the BAR was built for it,and a full auto M-14 infantry rifle is questionable.The M-14E2 was more in the BAR roll.but that is a step off the trail.The BAR would be just as effective had it been designed around the7.62 Nato round.

A full 20 rd BAR 30-06 magazine ,side by side with a full 20 rd M-14 mag,or FAL mag,is a fair comparison relative to the OP question.

IIRC,the BAR was 18 lbs.Save 5 lbs on ammo weight,you step up to a 23 lb M-60.

In business and profit,racing,warfare,elections,3% here,5% there makes the difference.

In the mountains,uphill,downhill,or sidehill,every pound matters.

 

[Bart B.]

History of the .308......

http://riflemansjournal.blogspot.com/2011/02/history-30-80-wcf-origin-of-308.html?m=1

The .308 was first used in competition at the 1963 NRA Nationals; it won the match. In three years, all the records shot with .30-06 rifles were broken. And there were so many unbreakable ties shot with .308's the NRA reduced the scoring rings. Both the Army and Marine Corps M14NM rifles shot XM118 match more accurate than their 30 caliber Garands. But the USN and USAF Garands rebarreled to the NATO cartridge shot XM118 match ammo more accurate than with 30 caliber barrels shooting M72 .30-06 match ammo. By the late 1960's, the 7.62 service match grade semiautos would shoot good lots of commercial .308 match ammo inside 4 inches at 600 yards from accuracy test cradles.

People rebarreling their .30-06's to .308 using the same quality ones as well as components saw accuracy improve by about 40% over the .30-06; 3-inch test groups at 600 yards was common in good rifles. And average velocities with the same bullets was/is about 100 fps less than the .30-06; so says SAAMI specs.

Both the military .30-06 and 7.62 NATO rounds were spec'd at 50,000 cup and the NATO round shot equal bullets out about 100 fps slower. Winchester spec'd their .308 at 52,000 cup as they used a slightly different system.

 

[DaleA]

Interesting article about the .308. Thanks for posting the link.

 

[old roper]

I was with 4th Marines when we made change over from M-1 to M-14 which was about 1963 and that was issue weapon we had in Vietnam.

Only thing M-14 was good for was more ammo shot. Every company 4th Marines had light machine then Battalion had heavy machine gun and there was lot of fire powder with M-1 and BAR down to squad level.

Marine Corp, every year it was required Marine had to qualify with his issue rifle as Marksman,Sharpshooter,Expert and if you had to carry pistol you had to qualify with that also.

Company I was with guys that had hard time with M-1 had same problem with M-14 and guys that shot expert with M-1 did same with M-14. And we had NCO that serve WWII and Korea with M-1 and I had 3yrs with M-1.

I left Vietnam 1965 and looking back almost 50yrs I think they should of kept M-1 till they figure out what they really needed which wasn't M-14.