Rings below neck of casing??

[Huckaby93]

Hey, guys.

I'm new to the forum so please don't roast me if this has already been asked and answered. I did a search and couldn't find anything quite like this.

I recently got a 16" 300 blackout upper which I believe has a SS 1:8 stoner barrel. I took it out to the range the other day and noticed odd markings on all of the spent casings I shoot from this upper. I was running 150gr Federal AE FMJs and also some other reloads my dad had made up (not sure the specs on those). Anyone ever seen this before??

Trying to figure out how to get a picture on here so if anyone has advice it would be much appreciated.

[bangbangping]

Pics definitely would help. You have to upload them to a hosting site like imgur and post a link back here.

[brutis]

Hey, guys.

Trying to figure out how to get a picture on here so if anyone has advice it would be much appreciated.

Follow this tutorial viewtopic.php?f=128&t=84314&hilit