Technique For Measuring Bores

[hobbler]

Just a passing thought for folks that also get frustrated with measuring three groove bore diameters.
This may be common place for all I know.

Stand up a minie on a hard surface and tap the nose with a hammer. Try it in the bore. Keep tapping the nose until there is resistance from the the base going in the bore. With the bore oiled, hold the minie by the nose and turn it in the bore. Tap it again. Twist it again. Keep going. After a while you get a shiny band of lead on the base of the minie that you can measure. The way that I do it (careful tapping and twisting technique, my hammer, my hand) I'll get right at 0.002" under the bore diameter. And, no longer have to borrow three point micrometers.

[Eggman]

Where does one find a three point micrometer?

[hobbler]

Starret makes good ones. Some have three bars and some have more.
http://www.starrett.com/metrology/me...re-Micrometers

I've used the pistol grip kind too.
http://store.greatgages.com/servlet/....+Pistol+Grips

[William H. Shuey]

They ain't peanuts $$$ wise.

Bill Shuey

[Don Dixon]

The simplest solution is to buy a set of plus size machinist's plug gauges in .001 increments in the size range in which you are interested; say .575 to .582. It doesn't cost that much, works in any bore independent of the number of lands and groves, saves a lot of time, and gives you exact measurements. Then size your bullet .001 smaller than the size of the best fitting plug gauge and you are good to go for size. Lube, powder, etc are another matter.

Regards,
Don Dixon
2881V

[Maillemaker]

I didn't have a set of bore gages so I did the same thing - I pushed in a tight-fitting bullet onto one band of the bullet, pulled it out, turned it a bit to hit the lands again, pushed it back in, etc, until I could spin the bullet in the bore.

Steve

[Southron Sr.]

I ordered a set of Plug Gauges from Grizzly. They go from .500 to .625 and cost only a little more than $60.00

Makes measuring bore sizes easy as pie!

[Ken Hansgen, 11094]

Brannen, Do you have one plug for every thousanth inch? If so, that's an awful lot of plugs!

[Don Dixon]

Ken,

Supply houses that deal with machinists and manufacturing companies sell relatively inexpensive boxed sets of gauges, and you can also buy single gauges. I have two boxed sets: one from .400 to .499, and the second from .500 to .599. As Southron pointed out, the number of gauges in other supplier's sets may vary. My two sets cover almost everything muzzle loading that I shoot. The smaller set was very useful, for example, in determining why an older Tom Ball revolver had deteriorating accuracy; the muzzle had become somewhat enlarged from cleaning over the years, since you have to clean M1858 Remingtons from the muzzle. One sees the same problem in muzzle loading rifles.

You don't need the entire boxed set for one caliber - if thats all you shoot -which is why I suggested a smaller sized range.

Regards,
Don Dixon
2881V

[Maillemaker]

Anyone have a link to these plugs? I had checked on McMaster-Carr but they did not go up to .58 sizes that I saw.

Steve