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What is the best way to measure the bore?

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I just got two Tingle pistols, and I need to measure each bore so I can determine which specific lead bullet (or mold) to buy...
 
My Tingle copy is called a .44 caliber and takes a .433 ball if that's any help to you. Otherwise, I would find a lead ball of about .45 caliber and smack it into the muzzle then take a course wood screw and thread it into the ball and pull it out then measure it.
 
I just got two Tingle pistols, and I need to measure each bore so I can determine which specific lead bullet (or mold) to buy...
The bore diameter( land top to land top) is best measured with a plug gauge. The groove diameter will require a slug driven through and if odd numbered groove will require a tri-mic or Powely gauge to measure accurately. Cerosafe will work too.
Remember your slug lands are the barrel groove diameter. Also the slug only measures the tightest spot in your barrel, most will vary in this diameter along the length a few ten thousands. .
 
Not familiar but on original guns I unbreech and lube the bores of barrels then drive an oversized ball into the muzzle and out the breech. Measure groove to groove then peel off the splines and measure bore diameter.
On a new gun get a set of expandable ball gauges and use them. https://www.mscdirect.com/product/details/01719293
Yeah, I have a set of split ball gauges and they work fine except on odd grooved barrels. They are great for chamber mouths and other round holes.
 
Good to keep in mind for loading patch and ball. A factory or anyone else`s formula suggested .433 may work well with a .427-440 ball depending on patch and or lube and bore condition. For best results testing with different size patch and ball is the only way to know. I prefer to taper lap and polish my bores to a larger patch or ball size. Easy loading and cleaning result. Some insist better accuracy results also. Maybe, but not worse scores in matches by my tests results. Good new for plinkers though. Most any patch and ball combo that loads without much trouble will most likely work fine to 25yds...c
 
Good to keep in mind for loading patch and ball. A factory or anyone else`s formula suggested .433 may work well with a .427-440 ball depending on patch and or lube and bore condition. For best results testing with different size patch and ball is the only way to know. I prefer to taper lap and polish my bores to a larger patch or ball size. Easy loading and cleaning result. Some insist better accuracy results also. Maybe, but not worse scores in matches by my tests results. Good new for plinkers though. Most any patch and ball combo that loads without much trouble will most likely work fine to 25yds...c
Most test patch thickness and material type by how it shoots but it can take a lot of trial and error shooting to sort out which is the best balance.
Torn patches seldom produce good accuracy but does not necessarily mean the thickness is wrong. A good starting place of a proper patch is material type which should always be of cotton and of a tight weave, thick enough to engrave the pattern into both the groove and land of the trail ball without cutting the fabric.
A good patch of proper weave and thickness will engrave the entire circumference of the ball , and after being shot will not be torn or have holes in it and will not be frayed except on the very edge of the perimeter. A tight weave is determined by holding up to a light source and not seeing large holes that the light shines through. I like cotton shirt felt about .018 or so thick.
Some like pre-cut and some like to cut at the muzzle. Niether seems to hold any advantage over the other if ball circumference is sealed.
 
What works is what is important, not perzact number sizes. Do this: take a large piece of the patch material you intend to use, put a ball of the size you guesstimate will be OK, seat about 2"down the bore the pull back out. Depending on ease/difficulty you had seating that ball, the rifling engraving the ball and yer judgement, you will decide if the ball is OK or neads to be larger or smaller. Of course, use only pure soft lead balls. Other techniques can measure for you. Like a brass rod with cerrosafe over it.
 
The best and most accurate measuring device is the pin gauge. You will need several pins of the approximate diameter, but these work on all barrels regardless of whether the number of lands is even or odd. The next is the split ball gauge set, for example here is a link to one of many offered on Amazon, HFS (R) 4 pc Full-Ball Small Bore Hole Precision Gage Gauge Set: Amazon.com: Industrial & Scientific. The last is the use of the inside measuring jaws of a Vernier caliper which are good for an even number of lands. Note: If you use the split ball gauges, you will need a micrometer or Vernier (digital) caliper to measure the setting of the split ball gauge.
 
I used my small hole gage and dial micrometer at the muzzles of the rifled barrels to arrive at 0.427 for a bore size.

I inserted pin gages into the muzzles (cannot access the breech end), and 0.425 easily slides right in and out, while 0.426 gently goes in about half the length of the gage before meeting resistance.

So now I need to determine which diameter lead round ball to order, as well as which size patch to use, so I can finally try my Tingle target pistols...
 
unfortunately I do not have the Tingle black powder revolver, that one would be neat

I did just buy 3 Tingle black powder single-shot target pistols in the past month (one actually marked .40 Cal., and the other two unmarked but measured to be approx. 0.426 bores...):
Tingle BP Magnum target pistols.jpg
 
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