So my stamp came in a couple weeks ago, and I just got the upper back from the engraver.  Time to try out the Scorpion at the range as a rifle.  I had shot it as a pistol once when I first bought it, but when it ran fine I cleaned it & put it away.  I had no intention of using the original sights, so I never bothered sighting it in.  

Now, I'm at the range today sighting in a MRO, and my first magazine was Hornady Critical Defense 135gr.  This is basically what I thought I'd leave in the gun when it's at home.  It's a solid defensive round, and I have a lot of them.  All of my shots grouped well at close range (10 yards) and sighting in the MRO was ridiculously easy.  The gun functioned flawlessly throughout the day.

Then I switched to some reloads I had wanted to try...Sierra 125gr hollow points with a mid-range charge of Titegroup.  These did not feel that different than the Hornady rounds I started with, and yet they landed on the target a good 6" - 8" away (high) from my point of aim.  I was pretty surprised at the difference between the 2 rounds.  It also seemed like a good zero at close range (10 yards) wasn't even close at 25 yards. I was in an indoor range, so wind was not a factor.

Curious if other owners have experienced similar results when switching between ammo brands, and also what distance you zero your Scorpions at.

Zero at 25yards. And yeah it makes a difference I was about 4 inches different from 147 to 124s. I'm pushing my 124 fmjhps pretty fast though with CFE Pistol.

Rifle rounds a few grains are no biggy, pistol rounds theres always a jump

Thanks for the info / feedback.