[xm177e2]

Is doesn't seem too outlandish that a .223 could have been sabotted into a .30.

But what would be the advantage of that (aside from the higher velocity possible)?

[Demidog]

But what would be the advantage of that (aside from the higher velocity possible)?

Especially if you're only going to fire it at 50 - 100 yards from the target. Would make a louder report.