2 Different Loads Hit 8 Inches Apart at 25 Yards

[Silver Jack Hammer]

Today at 25 yards with the same Colt’s SAA Lyman 429667 ww .431” Alox with the published minimum of Bullseye hit eight (8) inches higher than; RCBS 44-200-CM ww .430” Alox with a mid range charge of Trail Boss.

The shooting was done one handed.

I wouldn’t have expected a full eight (8) inches between these two loads at 25 yards.

[stubshaft]

Not unheard of, I've adjusted elevation on fixed sight guns by varying the powder charge.

[Bazoo]

Sounds like the dwell time on the first load is causing a higher POI. POI changes shows up more with single handed shooting it seems because your grip and overall stance is not as consistent. I bet if you up the bullseye charge to mid or mid-max level it will be much closer.

[Silver Jack Hammer]

I had zeroed this gun with the Bullseye load 20-30 years ago. I was puzzled how fixed sights could change point of impact with the same load as the Bullseye I was using today. Then Bazoo got my thinker thinken’ and hey, I zeroed this gun with this Bullseye load with a 2 hand hold.

Can’t wait to hit the range tomorrow.

[tazman]

Bazoo is correct.
Even with a 22lr pistol, the difference between one and two handed hold is apparent and often much more than you would expect.

[BK7saum]

Bingo. 2 hands hold the gun tighter and minimizes the muzzle rise compared to the 1 hand hold. Just physics.