Propogation of internet myth.
tracers are not such a good idea, anyway. most of those made since WW2 light up a dim red about 200 yards out, so the shooters position is not revealed. they also set fields on fire, and if of an early type, can destroy your barrel's accuracy potential rather quickly by corrosive effect.
The tracer materials don't even light off until well outside the bore. They're no more corrosive than the primers and propellant used to get the bullets going, and if it's U.S. 7.62mm NATO ammo, it's not corrosive, anyway. Many years ago, I bought several thousand of those 142gr M62 orange-tip bullets from Widener's, and have been loading them in my .30-06 rifles, .308 Win rifles, 7.5x55 Swiss rifles, and even my .30-30 Winchester Model 94, chambered one at a time. The red trace starts about 100 yards downrange.
Model 4006, you just got a good lesson in how nomenclature can trip somebody up.
Generation-X kids call the ammo used in SKS and AK-47 rifles "7.62", when they mean 7.62x39 M43 Soviet.
Post-WWII Baby Boomers who came of age before or during the Vietnam Conflict know that the ammo fed to M14 rifles and M60 machine guns was "7.62", aka 7.62mm NATO, aka 7.62x51, a very close cousin to the .308 Winchester round.
Of course, if you had a Tokarev pistol, PPSh submachine gun, or Czech CZ-52 pistol, then you would also feed it "7.62", but this time, it's 7.62x25 Tokarev.
You have a Mosin-Nagant, Dragunov, Romak, or SVT Tokarev rifle, it also gets fed "7.62", this time though it's 7.62x54R (sometimes referred to as 7.62x53R) .
I've got a Czech VZ-52 SHE rifle, made between 1952-1957. It also can be fed "7.62", but that particular rifle is chambered for 7.62x45 M52 Czech ammo.
So the opportunity exists for some serious confusion. Don't automatically assume the guy behind the gunshop counter is a nitwit because his jaw dropped or eyes rolled when somebody walked up to him and said, "I need some 7.62 ammo!"