See if your sized brass seats into your Barrel and falls out with gravity. Sounds like your not bumping your shoulder back enough like Zeneffect mentioned. I have seven 6.5 Grendel firearms and try to use the same ammo in all them. I use a Sheridan case gauge which replicates a minimum chamber. If your brass and ammo fits this case gauge the ammo should function in your 6.5 Grendel firearms.
I bought my Sheridan case gauge several years ago from Alexander Arms. One of the better purchases Ive made. These gauges are available from several vendors but currently out of stock at the link below.
https://sheridanengineering.com/product/...ion-gauge/
I bought my Sheridan case gauge several years ago from Alexander Arms. One of the better purchases Ive made. These gauges are available from several vendors but currently out of stock at the link below.
https://sheridanengineering.com/product/...ion-gauge/