Reload or sell my Grendel upper?

[White Smoke]

That was an interesting, but technical read! I have never looked for a flat spot in the velocity curve before. My method is to load up ladders for the different powders starting at the suggested starting load and going to the maximum suggested load in half-grain increments. I shoot four bullets at each powder charge and shoot a separate target for each load. That way I can line up all the targets on the dining room table when I am done and see how the respective groups progress as the powder charge goes up. In a perfect world, the groups start out large and then tighten up and then widen out again. The tightest group is the one I want. Now, depending on what the groups on either side of my "best" group look like, I may adjust the powder charge up or down a 10th or two to get to the actual "best" load. It's sort of like working a bell curve. Once I have found the best charge weight, I then play with the seating depth, starting at the maximum length allowed by the magazine. For this test, I usually shoot five rounds at the maximum length allowed by the magazine and then five more at a shortened length and so on. I will then set the targets out on the dining room table again and evaluate the changes, if any, in the seating depth. I will then chronograph my "final" round and call it good. I've been having a bit of a problem with accuracy and consistency with my Grendel. I get some tight groups, like under a half-inch and then go back with a five-shot group to confirm that load only to have the group blow out to an inch and a half. WTF? It was then I started playing with the seating depth, primarily because Barnes data showed their test COAL was 2.185" and I've never shot anything that short except for the really light bullets where you can't possibly get the 2.23" length and still have the bullet gripped sufficiently in the case. I'm shooting some Speer 90 grain TNT's at 2.19", but that's a short bullet compared to a non-lead 115 grainer. Anyway, like I said above, I'm going to the range this next week with some set out to 2.23" and we'll see what happens.