Three factors are involved, basically. What is the variation due to the gun itself (probably not able to determine other than from a Ransom rest properly set up), what is the variation due to ammo, and finally, variation due to shooter ability. in years past, before health related issues beset me, I could do pretty well testing handgun accuracy from a bench. Certain guns wouldn't shoot as well as others. Duh! I've gotten inch groups at 100 yards with a .17 HMR scoped Tracker on a totally calm day. Same with a 22 bull match barrel Contender. Super Blackhawk, 5" with the irons. 2 9, same. Same group at 25 yards, 5" , with a couple military autos, and one holers with a Gold Cup. The final answer, it all depends on gun, ammo, skill and then "conditions". All that said, my brother could shave 20% off my groups.