Is this throat erosion? Pictures included

[Pacarb915]

This is a pretty good explanation with good drawings of throat erosion.
https://www.fulton-armory.com/faqs/M14-FAQs/TEGauge.htm
Even though you take a really good picture, it's difficult to tell from a picture. It might be erosion or it might not be. How well does the thing shoot?

It's my first gun so it's hard to say how it shoots because I suck. But I was doing well with some egyptian surplus ammo. Me and a friend got a little carried away and put about 150 rounds through it in an hour It was really hot after that and we had a blown primer with the last round. next time I used it i was shooting Prvi Partizan soft point 8mm mauser ammo and I was all over the place, much worse than with the egyptian stuff. I was worried that the 150 rounds of egyptian stuff eroded it a bit.

Here's a pic of a chambered round:
Attachment 103686