If I wanted to compare its accuracy to a semi auto of some sort, would it be more fair to compare it to a semi auto with a barrel length in the 4 inch range. Thanks for your opinions
Aside from the effects of sight radius, barrel length has very little effect on accuracy. And, to the extent that it does, and there's a general rule to cover the effect, generally shorter is better.
A bullet traveling down a four inch semi-auto pistol will only have a little less than 3 inches of twist, while a bullet going down a 4 inch revolver will have more barrel to stablize it.
It doesn't matter as long as the combination of twist and muzzle velocity are sufficient to spin the bullet up to the rpm required for stabilization.
That can be done with a very short length of rifling as long as the muzzle velocity attained is sufficient to achieve the proper rpm. That would be true in all but extreme cases--someone cutting a barrel off
very short or someone using a
very light load or a
very heavy/long bullet for caliber. It's not something that would ever be encountered with a factory handgun and factory ammunition unless one or the other were defective.
I think you will find revolvers more accurate at longer distances.
If one handgun is appreciably more accurate than another at one distance, it will also be more accurate at any other practical distances.
To the extent that revolvers are more accurate than semi-autos, it has little to do with barrel length and a lot to do with the fact that revolvers have fixed barrels while most locked breech semi-autos have floating barrels.
depends on how far the bullet has to travel 15 feet or 75 feet.
Unless the bullet is on the hairy edge of being stabilized, it won't make any practical difference how far the bullet has to travel. It's theoretically possible that a bullet that is marginally stabilized might become unstable after it travels downrange a significant distance--but again, that would be a very unlikely situation. And even then it would take more than 20 something yards for a bullet's spin to slow enough to destabilize.
Yet on revolvers, barrel length is measured by the length of the barrel only, not taking into consideration the length of the cylinder/chamber.
Where this would make a difference is in muzzle velocity--except that a revolver has a barrel/cylinder gap and a semi-auto does not. It's usually reasonable to make the assumption that the difference in muzzle velocity due to the different methods of measurement will be more or less cancelled out by the difference in muzzle velocity due to gas pressure lost to the barrel/cylinder gap. In reality, there are so many difficult to measure variables that affect muzzle velocity that it's not worth agonizing over. If you want to know the muzzle velocity of a particular gun/load combo, either get a chronograph or borrow one.
Here's an interesting website that studies velocity differences due to barrel lengths. They don't get into accuracy much, but it's still a valuable resource. One thing you'll note is that while shortening a particular barrel will reduce velocity out of that barrel, if you compare a variety of barrels of the same length, the muzzle velocities can vary considerably from one to the other.
http://www.ballisticsbytheinch.com/
Getting back to the accuracy issue, here's a chart created from the data found at this website.
http://www.accuratereloading.com/223sb.html
The chart below shows the accuracy of a rifle that was progressively shortened from 22" to 10" and tested for accuracy at each length.
The first important thing to notice is that there wasn't much effect on accuracy at all. The 22" group was about 0.62" and the 10" group was about 0.65". One could characterize all of the groups as being 0.58" plus or minus 0.07". Plus or minus seven hundredths of an inch is not much variance.
Also, from the graph, it's clear that the best accuracy was not attained with the longest barrel lengths. While the worst group was with the shortest length, the second worst group was with the longest length. Besides, the graph clearly bounces around in terms of group size as length changes. It's entirely possible that the 9" group would have been tiny. After all, the third and fourth worst groups (at 14" and 16") were right next to the tiniest group shot with the 15" barrel length.
