The Gun Thread

Your the first person I've heard describe that. The only AR-15 cartridges I've read about are shorter ones limited to the standard action and bolts, while 308 is like you said ar10. This must be a new design. Who invented it?

They were designed by Eugene Stoner... actually, the AR-10 was his first design. Then it was modified and reduced in size for the new military cartridge, the 5.56, or as known in the civilian world, the .223
There are subtle differences in the 5.56 and the .223, but they can be fired in the same firearms, generally.
But, the AR-10 was designed first, in 7.62 Nato, or as known in the civilian world, the .308 Winchester.

Many people recommend that you do not fire 5.56 ammo in a rifle specifically chambered for .223 Remington.... The 5.56 is loaded to slightly higher pressures, and could cause issues. .223 in a 5.56 is perfectly fine.

I think it's the opposite in the 7.62/.308..... the civilian version .308 Winchester is loaded to higher pressures than the 7.62x51 Nato.

Yep, that is how I recall it, >556 has a slightly longer throat.
So much to learn and grow min with the shooting sports.
We have a local gun show coming up in first weekend of January, I wonder what will follow me home?
Will be watching for the Ruger small frame AR and a Ruger bearcat 22.

How do they lose so much weight when they become civilians?

I always assumed the numbers referred to the length of the shells. But what units is the military measuring in, what units are we measuring in as civilians and why are we not all measuring with the same standards?

Is the United States army using metric? Could that be considered treasonous?

308 is a caliber, a caliber is an inch. .308 is .308 of one inch.
7.62 millimeters x 51milimeters is the NATO designation.
5.56 millimeters x 45 millimeters is also our NATO designation.
Gauge is the number of lead balls of that diameter to weigh a pound, 12 gauge are 12 lead balls of that diameter to weigh a lbs. 16 gauge, 20 gauge, etc.
Want more confusion? Then we go to 410, don't recall right now but is roughly equivalent to 45 caliber.

I thought so. Our own military done turned traitor on us and started using metric. The measurements of the enemy!

Blame it on NATO.... and then they won't pay their bills!

Yes.. the SFAR is very nice. I really have been enjoying mine. Still working on finding "the" load... it's very pleasant to shoot.

You got it mostly right... the number after the "x" is the length of the case. The number before the "x" is the diameter, or caliber of the cartridge. 7.62 mm equals right at .308 diameter (caliber).... so there are quite a few 7.62mm cartridges... the number after the "x" tells you which one it is. 7.62x39 is the 30 caliber used in the AK-47's and SKS rifles of the soviet bloc. The 7.62x54 is a more powerful cartridge, about equal to our 30-06 military cartridge. The7.62x51 is the slightly shorter cartridge that is the equivalent of our .308 cartridge.
The 30-30 cartridge would be called the 7.62x51R, the "R" being for "rimmed"... the length of the case, though, is 51mm.

My rule of thumb, when trying to figure out "caliber" is to multiply the metric number by 4... that gets you in the ballpark for "caliber".

There are lots of strange things in the world of firearms and cartridges.... like @shittim mentioned... the shotgun "gauge" thing. All shotguns are "gauges" except the .410, which is bore size.... so it's correctly the "410 bore", not 410 gauge.