On a nice day at 100 yards I have considered myself a .5 MOA skilled shooter for the last year as my groups have gotten better as I practiced with a purpose. That seems to be the lower bound on groups I've been able to achieve consistently and rely on. Will some be higher, sure, some lower, sure but I'm surprised if something is outside the .4-.6 range. When shooting to test or practice I have always shot 5x5 groups taken the ES of each group, averaged it, like most guys have. Here is an example from 4/2/18 this year.

I started to have a problem that my groups were getting larger recently despite nothing changing with the gun or load. I was frustrated enough that I took out a few other guns and started to notice I was regularly getting .3MOA wide groups but .9 MOA vertical. I figured I must have developed a bad shooting habit suddenly and not realized it, so checked my bipod pressure, rear bag hold, etc. and things got better vertical but -worse- horizontal now.
I double checked scope tight, muzzle brake on, etc so I'm 99% sure its not the equipment, which means it has to be me. So I recently went out and shot some larger shotcount groups (15) at 200 yards and after reading Litz's book decided to look at mean radius as a better metric of how my shooting was doing.

Low and behold - I couldn't keep the ES of 6 groups under even 1 MOA at 200 yards despite this being the same load/gun as shot on the target above. These were slightly different seating depths on the bottom 4 targets (wondering if maybe my load just needed a re-tune) but they're all statistically identical. Seeing the higher number of shots in a groups at 200 yards though does show that in all but one group my wides spread shots are low left and high right, which seems to confirm to me that its something about my shooting thats opening these groups up with the outliers?
99% of my prior shooting for groups was at 100 yards using 5x25 and the ES methodology to figure out my accuracy. If you believe the math in Litz's book, that should have approximately the same statistical confidence as shooting groups of 15 with mean radius. That means a .5 MOA group from a rifle and a 1.0 MOA group (let alone 4) shouldn't happen by "chance" - I'm doing something wrong suddenly...
Any suggestions where to try and get back on point?

I started to have a problem that my groups were getting larger recently despite nothing changing with the gun or load. I was frustrated enough that I took out a few other guns and started to notice I was regularly getting .3MOA wide groups but .9 MOA vertical. I figured I must have developed a bad shooting habit suddenly and not realized it, so checked my bipod pressure, rear bag hold, etc. and things got better vertical but -worse- horizontal now.
I double checked scope tight, muzzle brake on, etc so I'm 99% sure its not the equipment, which means it has to be me. So I recently went out and shot some larger shotcount groups (15) at 200 yards and after reading Litz's book decided to look at mean radius as a better metric of how my shooting was doing.

Low and behold - I couldn't keep the ES of 6 groups under even 1 MOA at 200 yards despite this being the same load/gun as shot on the target above. These were slightly different seating depths on the bottom 4 targets (wondering if maybe my load just needed a re-tune) but they're all statistically identical. Seeing the higher number of shots in a groups at 200 yards though does show that in all but one group my wides spread shots are low left and high right, which seems to confirm to me that its something about my shooting thats opening these groups up with the outliers?
99% of my prior shooting for groups was at 100 yards using 5x25 and the ES methodology to figure out my accuracy. If you believe the math in Litz's book, that should have approximately the same statistical confidence as shooting groups of 15 with mean radius. That means a .5 MOA group from a rifle and a 1.0 MOA group (let alone 4) shouldn't happen by "chance" - I'm doing something wrong suddenly...
Any suggestions where to try and get back on point?