Aero M5 upper reciever question

[Dildobaggins]

So I just picked up an upper reciever for my AR10 build. Built a few ar15s all went smooth as silk. I pulled the M5 upper reciever out of the box and noticed the threads have indentations in the thread,s directly in line were with the ejection port rod. Am I going crazy or does this picture of one have them too? Anyone else have the M5 upper with the same thing? Thanks everyone.

 

[smokin.338]

yes

 

[kentuckyMarksman]

Upper in picture has them too.

Can't comment on if you're crazy or not.

 

[Billiam1211]

That’s normal. I’ve had a couple of those uppers and they all have that.

 

[Dildobaggins]

Upper in picture has them too.

Can't comment on if you're crazy or not.

Lmao!

 

[Dildobaggins]

That’s normal. I’ve had a couple of those uppers and they all have that.

Awesome. Appriciate it!

 

[hlee]

I suspect you’ll figure out why they are there when you go to install the ejection port cover...

 

[Dildobaggins]

I suspect you’ll figure out why they are there when you go to install the ejection port cover...

. I bought it fully assembled. In the back of my mind, I had a feeling thats why they were there, but I kept doubting myself.