Ok, sorry to bring this thread back from the dead but I got my Knight KP1 inner diameter measured "Slugged" as you say. Going to get my CVA done but I thought I would post up the results of the KP1.
Well I first smashed a lead maxi-hunter and pulled the breech plug out then pushed it starting from the breech. It smashed in nice and tight but after just about 2-3 inches got really easy and jut pushed right out. What I mean is the ID down by the breech is smaller then the barrel???????
So I got another and this time went down the bore. It was the same all the way down tell about 3" from the breech and sure enough it tightened up. So I pushed it backward out of the bore and measured it with a real nice caliper and lone behold it sat right at .5025", so my first measurement was correct.
If I were to have pushed it the last 3" or so out of the breech it would have been right around .502" to .5015", well I assume anyway. I look forward to do the CVA which I know it's a larger diameter.
So, how could the barrel be different ID guys?
