Is all 7.62x51 U.S. made ammo non corrosive?

ALL US military ammo has been non-corrosive since 1953, and nearly all foreign ammo since 1974. This applies to NATO ammo, as some like the 7.62x54R still is furnished with corrosive primers.

To my knowledge, U.S. arsenals and contractors never loaded 7.62x51 with corrosive primers. I shot a lot match rifle and service rifle in the 1980s and 1990s and never heard a word about issue ammo with corrosive primers.

Certainly anything with the NATO standard mark on the head -- a circle surrounding a cross -- is non-corrosive no matter where it was manufactured.

As you say, foreign ammo is less certain. The cartridge is loaded all over the world, so I would be suspicious of foreign ammo dating earlier than the mid-1970s, especially if you have no idea where it was manufactured.

Yes.

That type of ammo was phased out of military & commercial use in the USA Well over 50 years ago. The culprit is mercuric salts in the priming compound in the primers. Upon firing this ammo, these corrosive salts were deposited all inside the barrel of the weapon.

If these salts were not removed, they would attract moisture and corrode (rust) the inside of the barrel. Swabbing the barrel with oil would not stop this process. They would rust under the oil.

The only solution is to remove the salts. This is easily done by using a water-based solvent, or just water. The barrel must then be dried and then oiled to prevent rust.

The 7.62mm NATO was invented in the post Corrosive era. So your fine.

All American made ammunition is non corrosive and I BELIEVE the same is true for ALL ammunition currently being manufactured world wide now days

Not current production. Older surplus up until around the 1970's may be.

Yes unless it is old ammo.

But either way just clean you rife good if you use corrossive, and you will be okay.