Who made the barrel for your AR? Some of the barrels have shorter throats than others and you will run into pressure much quicker with a short throat. The SAMMI chamber for the 6.5 Grendel has a compound throat, look up a diagram and you will see what I am talking about. When you use a bullet comparator or other method to see where you bullet is hitting the lands like in a bolt rifle etc. you may be toughing the compound throat area and actually not the lands. Also like I stated in my previous post "Don't try to hot rod the Grendel in an AR". By the time you start seeing flattening primers and ejector swipes on the case rim you are already WAY over pressure. You can brake a bolt or will just beat your AR up with the higher pressure loads. If you have a Bear Creek Arsenal (BCA) barrel good luck in getting it to shoot. Most are crap, it is a hit or miss with them. My first Grendel was a BCA 20 inch complete upper and I had to send it back for replacement because it shot an average of 5 inch groups, and that was an ordeal just to get someone on the phone that knew what they were talking about. The crown looked like it was done with a side grinder. It took about 100 rounds down the bore of the replacement before it started to settle down and shoot consistently without flinging fliers. It is picky about what it want's to shoot but I did get it shooting sub moa. In the ordeal I probably could have bought a high quality barrel that would shoot from the get go and saved money counting all the components and gas to the range etc. I built another 6.5 Grendel using an 18" Oden Works barrel that shot great from the get go.