bore dimension tools

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BJung

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What do I use to determine the actual bore for my rifles?

I was thinking of finding pure lead and casting it in one of my bullet molds. Then can I start it with a steel or should I look for a brass punch? Can I use a wooden dowel, or can I use a steel rod, or should I buy an expensive brass rod?

I don't want to damage my bore so I thought I ask first.
 
burbank_jung said:
What do I use to determine the actual bore for my rifles?

I was thinking of finding pure lead and casting it in one of my bullet molds. Then can I start it with a steel or should I look for a brass punch? Can I use a wooden dowel, or can I use a steel rod, or should I buy an expensive brass rod?

I don't want to damage my bore so I thought I ask first.
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Do not use a wood dowel to slug your bore...they have been known to break and jam in the bore.

I have a couple of brass rods the I think I got from Tractor Supply Company...I do not consider them as being "expensive".

Generally, using a steel rod to push a lead slug though a barrel is thought to be a questionable practice and less safe for your barrel than brass.
 
Punch Set

Do you start your lead bullet with a steel punch set or did you look for and find a brass punch?
 
You reminded me that I have some old split shots in my tackle box. I could give them a bite test and compare them to a canister of lead shot I've had for decades. Hopefully that is pure lead and I can use it.
 
Yep. Case or oval or you can pick up some slightly oversize pure lead balls that Hornady makes for BP guns. This process is called slugging the bore. Run a lightly oiled patch through the bore first. Then use a short length of brass rod or wood dowel and a plastic head hammer to tap the slug until it is just started into the rifling. After that, you can push it through the bore with either a longer rod or dowel or a cleaning rod. The wood won't splinter or cause problems if it is not pushing on a point, but it does have more rubbing friction with the bore that might interfere with how well you can feel the slug's progress down the bore. A cleaning rod has lots of clearance and the handle gives you control so you can push the slug through slowly (a couple of inches per second or so) which will let you feel irregularities in the bore. If the bore is tapered in either direction, the slug will feel different depending on which direction you push it through, so I slug from both ends where I think that may matter. The diameters across the mirrored lands or grooves will reflect the narrowest part of the bore the slugs went through.

You want to use a micrometer with a scale for tenths of a thousandth of an inch to make the measurements with a gentle hand, as firelapping or other actions you take to correct constrictions or roughness will have effects that are usually less than a thousandth of an inch, and best accuracy bullet diameters are often in the half-thousandth resolution range and you'll want to be able to measure those. This outfit's least expensive 1" OD micrometer is $21. They also have a 5-flute V-anvil micrometer to use on slugs for 5-groove barrels, but those cost five times as much. I've bought from them before when I needed an inexpensive tool for something, and they have delivered what they advertised.
 
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