New Grendel upper won't chamber a round properly

[jertex]

Did you resize the brass prior to reloading it?

Yes.

If it was fired from your sons Grendel those brass would be formed to his chamber, not yours.

I understand that.

Will a reloaded round fall into the chamber without the the BCG installed? Does it also stick?

No, it sticks and will not fall out. I did try an empty, resized case, and it doesn't stick as badly, but it still sticks and won't seat all the way.

What did you set the COL of your reloads too? What bullet are you using?

2.260/123gr Hornady ELD-M & 2.248/123gr Hornady FMJ Midsouth shooter's supply exclusive