Crazy lot-to-lot consistency with Staball Match?

[FrontRange]

So, I’ve been using Staball Match for a couple of different cartridges (6.5 Grendel, 6ARC, AND 223) and have been generally quite pleased with velocity, temp stability, accuracy, and sds. I bought another pound and loaded some 6.5 Grendel with an established 31.0gr load at 2420fps (inline with Hornady and Sierra data) without worrying too much about lot differences and needing to work up because of the relatively low pressure in a gas gun. However, I didn’t expect a 120fps DROP in velocity. I went home and checked my charge weights (they were the last charges I dropped) and, right on the money, 31.0. This is basically a full case up into the neck so I don’t think I can get much more powder into it. I haven’t tried this lot in any other cartridges but, at worst, I can use it for 223 practice. I’ve never had anything like this happen at least not anything that changed velocity by more than 50fps. Thoughts? Does this happen? Thanks, I’m a little at a loss?

 

[A382DWDZQ]

Someone left a tip on here a while back to always set aside a handful of the old powder loads for benchmarking when you move lots. Do you have any of the old loads, and/or did you already check against them? Fire one new and one old in the same session? Lot variance happens, that is my understanding of why QuickLoad has the 10% +/- lines. Good luck solving this!

 

[FrontRange]

Someone left a tip on here a while back to always set aside a handful of the old powder loads for benchmarking when you move lots. Do you have any of the old loads, and/or did you already check against them? Fire one new and one old in the same session? Lot variance happens, that is my understanding of why QuickLoad has the 10% +/- lines. Good luck solving this!

Thanks and that’s smart but I ran the last can out. Loads were from the same set of prepped brass, same primers, same projectiles, measured on the same scale that is regularly checked during loading (my sds are still good enough), shot 2 weeks from each other and I’ve shot several from the previous loads outside more recently with expected changes due to temps. Only thing switched was the powder. Both strings were shot at an indoor 100 yard range so I don’t think it’s environmental. I’ll try to fit more powder into a case but it’s already pretty compressed. I’m used to some variance but I’ve never seen that big of a drop/increase, although I guess it falls within a 10% variance.