Normal M&p9 primer markings?

[G60]

These primers are from a brand new smith & wesson m&p 9. Put about 400 rounds through it yesterday and noticed markings on the primers I'm not used to (the only other handguns I've owned were in .45)
hopefully it shows up in the pictures, but all the primers have the firing pink mark with a 'teardrop' shaped bulge around it.
My first guess is the bulge is due to higher pressure of the 9mm cartridge (even though these were mild 115gr loads), the firing pin hole being larger than the firing pin, and the teardrop shape being formed as the cartridge is quickly ejected.
Is this normal for an m&p9 or something to worry about?

[Shenaniguns]

Normal

[gef]

I have the Smith M&P in 9mm and that's the way it is. I like mine alot.

[OneSevenDeuce]

Interesting. You learn something every day.

[45R]

Dude your gun is FUBAR send it to me and I'll make sure you get it back in proper working order

Its normal, enjoy shooting it!

[smarter]

ditto to all above post.

[evolixsurf]

yup, the m&p's all leave those markings.