Finally got motivated and got the 300 bo together, first time playing with this cartridge and am curious on how my brass Looks and leads to buffer question

16" BHW Carbine gas 300 barrel just plan on supers for now, anyways took a quick drive and wanted to test it out, fired a few different factory loads and used a lancer and Troy mag without issues, locked the bolt back everytime.

Upon looking the brass seems dented pretty good on the necks, everyone , I reload and understand the 556 cases get this from the shell deflector.

It is hitting the deflector, maybe to hard? Only had a carbine buffer on me and normal carbine spring,

Is this normal per say for the shorter cartridge? Or overgasssd some and should bring s H buffer to try next?

Anyways some quick pics










Any input? Something or just shoot it?