Indeed, the bore is .720, as measured with a snap gauge. I can find no restriction in the barrels whatsoever. I measured from six inches down the bore to the muzzle. If I could figure out how, I would measure all the way to the breech plug. I will not attempt to remove a breech plug to measure it. I found this out, after I asked the question, so my apologies to the forum. Thanks to you Greymule, for your response.