BTW: I just checked another rifle in my possession. On one of them, I found a closest but barely visible to the pictured egging spot in about the same location - about 2/3 from the end of the barrel and 1/3 to the end of the handguard.
On one of my M&P15-22 rifles visible egging spot on about 2/3 from the end of the barrel and 1/3 to the end of the handguard.
Is it a common thing from manufacturing, or may it cause the barrel faulty?