Thanks again Jim and Rocketman. I understand all of that. The thing I don't understand is few have said gun was either honed or backbored. My reasoning is that if that were so, the bores would be larger not smaller.
Their assumption is that they ARE larger. The assumption for backboring is that the bores were once .717 for their entire length, and they became larger....724-.727 by backboring. I've no reason to suspect they were backbored.
This is what I have come up with since the last post. Using plug gages, right barrel from breech; Left barrel from breech:
.727 in 5" .727 in 10"
.726 in 9" .726 in 24"
.724 in 22 15/16" .724 in 24 15 /16"
.722 in 25" .722 in 25"
.717 in 27 1/16" .717 in 25 7/8" Barrels again are 28" long, and have not been cut.
Something's wrong here. Your measurements don't jibe. Above, you're getting .726 within 5-10" of the muzzle. These numbers suggest to me the chokes are virtually identical...commencing ~4" back from the muzzle and constricting ~ 9 points in both barrels. Nominally, essentially constant .7265 for 20+ inches, then constricted to .717 in both. Earlier you said... "Small Bore, I did that, when I put the gage into the muzzle end after being zeroed on the .700 ring. It read .718 to the full depth of 12", withdrawing it slowly read the same until it was out of muzzle."
I think you had sticky balls. 
So what's the bore diameter 6" in? is it .718 or .726? [color:#FF0000]
