Did I just happen to run into some ballistic coincidence here, at 25 yards? This is primarily a Night Vision Gun, firing Subs for neighbor relations. But I wanted to see where 110gr TAC-TX would print, so I had an idea/offsets entered into Strelok, etc... 10.5", Rugged Razor, Sandbagged both front and rear, using Holosun 503G-ACSS w/3x Magnifier. No chrono, but using a mrgunsngear video, probably ~1000fps for the Subs, and 2200fps for the TAC-TX. Surprised me - I'll probably back up to 50 and see what's what.

Bottom Left was last 200gr group, went 1 click Right and fired Top Right Tac-TX group.

What's the question?

A 25 yard zero for supers/subs are very close when the distances are so short and time of flight so short that gravity does not have the time to do much to the trajectory.

Lets take your 1000 fps subsonic speed. It covers 100 feet in 0.1 seconds or 75 feet (25 yards) in 0.075 seconds. In 0.075 seconds a bullet drops 0.090 feet or 1.08" due to gravity... if we dont account for air resistance or for the fact the barrel is not level (in actuality it is less than 1.08" of drop) and that is the MAX drop we could get from initial horizontal muzzle line. A bullet moving just over twice as fast will drop less, but still has drop. We would expect only 0.5" to 0.75" vertical impact difference at 25y without a zero adjustment MAXIMUM, not accounting for air, natural POI variation, etc.

A 25 yard zero for 300 BLK subs is almost a 50 yard zero as well. You could zero for 50 and shoot 25 with no hold off and be fine. Not so much for supers... they diverge more from 25 to 50.

You really want a 50 yard supersonic zero. It will be less than an inch low or high from 30 yards to 110+ yards... then it drops like a rock. A 25 yard supersonic zero has a longer distance to cross your sight plane but is much more rainbow like and deviates more from 25y to 125y.

Note how MOST of your subs fall below the centerline of your POA at 25 but the supers are dead center? That is typical. The large group size is what caused the high rounds and probably at least one impact centerline. The rest are just a bit lower... as expected.