If the handle of your gun were in my hands, 3.5 inches would be perfect!
What I'm getting at is, what is your capability with a revolver? They aren't the easiest thing to shoot tight groups with at 100 meters! If you have proven that you can shoot tight with any other revolver or load, then I'd suggest an LFN in 230 to 250 gr. It is capable of an inch fairly regular, and two inches consistently at 100 meters, if the gun is lapped, if the cylinder throats are slightly larger than the barrel, if the bullets are carefully made and are precisely fitted to the gun. -- I've spelled out perhaps a bit more than one can expect with an over the counter gun, and with commercially cast bullets, which Montana bullets are, though they are definately of very high quality and hand cast.