Chamber differences in Sixguns

Mak: I think in order to tell for certain, you would have to test each chamber separately. Shoot five rounds through one cylinder chamber for group, then do each chamber in turn and see if one is worse or better than the others. I have measured the chamber throats on my Colt New Frontier .45 and they seem to vary about .0001-.0005 from the nominal .4535 dimension that seems to be my cylinders measurement. I know that .452 size bullets don't shoot real tight groups in that gun, so I need to try .454 I suppose, and I don't cast so I buy my cast bullets from whoever has the size I need and want. Has this made any sense? Chris

Interesting subject. Although my skill at the range and reloading bench probably negate any differences in the revolvers chambering, I have made a few measurments on different guns, a Dan Wesson in which the barrel was  not parallel with the bores, (example the bullet had to make a slight left turn in the forcing cone). A Tarus that the difference in the forcing cone to cylinder gap varied enough as you spun it that you didn't need a feeler guage to tell all was not well. I believe the high quality guns are line bored for the most part, seems like a good way to go. One fellow we shoot with uses the same bore for all 12 shots, hits a 4" plate at 150 yards pretty consistantly, so there may be something to it once you reach that skill level. I have tried with my FA to find a difference in the chrono between five shots from the same bore and one shot from each bore, about the same results as when I sorted my brass by brand, or when I weigh individual charges and compare to the charges the powder measure throws. No statistical difference (again, at my skill level with my chrony and a high quality revolver).

I agree Al, I don't think there is enough variation unless you happen to get a seriously flawed gun. In my case I only want to know the size of the cast bullet I should use, not if each chamber is exact. My shooting is mostly for fun and, since I don't hunt anymore, I just care about hitting the target and having fun shooting my Colt. Chris

Doubtless it is that skill level has much to do with discovering weaknesses and limitations in any device, including a sixgun. Yes, for the fatally flawed, any modicum of skill will reveal the goblins. I find it telling, however, that in decades past, the prevailing wisdom was to focus on groove diameter as the be-all, while today, few think about this dimension, and instead focuses primarily on chamber throats. Throats themselves are only one aspect of correct chamber size, but they sure get the attention. I have noticed that chambers with excessively small throats will make shooting cast bullets a lively exercise. Large for diameter throats may adversely effect accuracy-depending on load and other circumstances, but small for diameter will spit hot lead all over in a fiery shower!