Quoted:
What the hell am i looking at?
It looks like it's in one of the grooves, and not on a land... Will it blow up? PROBABLY not... Is it a good idea to shoot it? Absolutely not.
The optimist in me would fire it, (maybe remotely, using a piece of string, depending on how brave/not brave I'm feeling), and see.
But the pessimist in me tells me to strongly advise anybody else against doing as I do.
Maybe use it for a cheap dedicated .22 upper..., or chop it down and put an extended flash hider on to make up the difference, or make a pistol barrel out of it.
Like I said, I highly doubt that it's going to cause the weapon to explode, but it almost certainly ain't gonna be accurate. And that small small chance that it MIGHT cause problems, should be enough to give them pause, before firing a full-powered rifle round through it.
Another option is to just
trash it set it aside for a possible future project, and get another replacement barrel. Chalk the cost up as tuition, toward the School of Hard Knocks...