Slugging a barrel?

[Fourty5seventy]

Today I wanted to slug the bore of my H&R buffalo classic 45-70 so I got some round balls in .457 and went home and put gun oil down the barrel and coated the ball with lube. Then I used a plastic hammer and tapped it into the barrel. To my suprise it went through with about as much effort as a cleaning jag with a patch on it. There were hardly any marks on the ball just the part where the lands were. What are your thoughts on my bore dia. ?

[DaveF]

Put the sprue cut off mark of a .457 ball against one vise jaw, and and squeeze the ball slightly in the vise to enlarge it's diameter.
Center this facing out on top of the bore, and then tap it through the barrel.
The expanded ball should then show engravings of both the lands and the grooves, which you can then measure.
45-70 bore diameters usually run around .457 - .458, so you need larger than that to accurately measure the result.
Regards, DaveF.

[Wayne Smith]

Or get a hollow sinker from the fishing section of your sports store. They work very well. Then measure only with a micrometer.

[Unclenick]

Agree with the micrometer, but the fishing sinkers where I am in Ohio don't seem to be pure lead anymore. You want pure lead, or something not more than about BHN 6 or so, for its lack of elasticity. I've run cast alloys down a bore and felt no unevenness; just a hard push all the way. That's due to springiness of the alloy pushing out against the bore. A pure lead slug in the same bore moved more easily and revealed rough and tight spots immediately.