So I think I may be on to something.
On a whim, I dug in the cabinet and pulled out a box of 115 gr tula brass max . (I shoot reloads almost exclusively - mostly 147's over TG, or 124's over ETR7 or E3 or 231) I only have 147's at the moment.
I loaded up the tula brass max 115s and got this
5 rds each diamond as usual
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10 rds
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Now - these reloads work superbly in every other firearm I own. Why would they NOT work well in this gun? What could I be missing here?
Switched back to the 147 reloads and got this 5 shot group:
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