YIKES---Hi Mounts or ? (video)

[ImAfossil]

Trying to keep this simple (under TRAINING). Normally my .204 is zeroed at 200 yards. My hold at 300 is about 5 inches up from center mass with a 50MM lens and hi-mounts. I switched to a 40MM, stayed with the hi-mounts and re-zeroed to 100 yards due to (a long story that is not important) and my hold went up to 7 inches over center body mass in this video.

The largest variable is the shooter. I understand that. I had time, a rock steady rest and a smooth trigger and follow through pull.

This video shows 2 shots at a chuck that has me baffled. Both shots are down the middle at 300 and is a KO with my 50MM zeroed at 200, shooting downhill into a steep bank back stop.
What went wrong with my hold over / bullet impact ? Does the 100 zero & 40MM with hi-mounts make these 2 shots really ugly, like a foot high at 300 yards ??????????? The 24 second video is better at full screen. Also looking for an answer. I am friggin' lost.
This H&R shoots so good, I will get a Smith to cut the hammer ear down to accommodate the offset for clearance on the eye relief so that I can go to low mounts. These are the first HIs I have ever used----THEY Gotta' Go !
fossil

. equals bullet impact

* equals my hold over