If you were to put each gun in a vice (Ransom Rest) and fire it at 30' feet with no human interference, the guns might have about the same size group. Mechanically, they both can shoot bullets pretty straight for 30'.
However, the interaction of these two different sized guns with the shooter means the smaller gun will be harder to shoot accurately for many people. The smaller grip, shorter sight radius, shorter barrel producing more blast and muzzle flip, different trigger pull configuration, lighter weight, and other factors make smaller guns more difficult to shoot. That is, until you learn how to shoot it well despite these differences.
Have someone help you with proper grip (slightly different for each of your guns), sight alignment and trigger control. Practice with each gun shooting from a rest so you can eliminate some human shake and concentrate on the above three fundamentals. When you are not satisfied with your pistol accuracy, shoot at a closer distance so you don't get discouraged, concentrating on the three fundamentals. Go back to unsupported two handed shooting at 15'; then 21'; then 30' again.
AND, dry fire at home. A lot. Save ammo and range time. Your trip to the range should confirm that which you have practiced and learned at home works. When dry firing, your sights should not move off the target when you operate the trigger. Minor wiggles produce larger than expected accuracy errors downrange. Be precise.
Good luck.
