Musket bore diameter - how to measure??

[Jkrem]

After a great conversation with Dave951, I now know I really need to measure the diameter of the bore of my Parker Hale Model 1861. Note, I do not have the proper machinist tools to gage this, and need a lower tech method. I can’t find any decent videos on YouTube on how to do this, and can’t find a past discussion or sticky here. I do recall reading someplace that you can drop a heavy piece of brass rod into the barrel, then carefully hammer a soft oversized round ball into a lubricated bore. Then, using gravity, hold the rifle upside down and shake up and down until the brass rod ejects the slug. Has anyone actually done this and had success? Could you do the same thing with some cerrosafe poured into the last few inches of the bore? As always, I appreciate any help and suggestions. Jkrem

[junkbug]

Skirmishers simply use several different minies; trying lets say .577", .578", and .579" to see which one is a snug finger fit in the muzzle. You don't push it in all the way, just deep enough to get a feel. Too snug, and it will be difficult to load after many shots. So you wuld need someonr to loan or donate to you several test boolits.
Pretty low tech.

[mooman76]

I have never done the lead slug thing on a muzzle loader but I hear it enough, I'm sure it would work.

[Good Cheer]

A manner in which the bore may be checked is to take a good pair of pliers and a minie ball. Hold the minie by the nose and use the rifling to machine the lead down as you carefully move the skirt into the bore. After doing that with a few minie balls and getting a good feel for it, measure the diameters on those minies and figger out what it is. If you don't have the measuring device to use then it becomes a matter of hunting and pecking with various sizes of minies (but then you're going by what somebody else says they are).

Question for the forum: Are PH 1861's known to have much variation in bore diameters ?

[FLINTNFIRE]

Oh another lets complicate things , have a minie ball try it and see , now measure it bigger or smaller , easy to do , have the 53 58 and 61 parker hale and other makes also Zouave , I try to keep it simple , yes I know different makers made different bore and twist , measure twist with a tight patch and try a slug for fit and it should be easy , never used machinist tools and never tried a brass rod and a slug shaking , it like a lot of things is keep it simple , try some minies as the idea is a easy fit down skirt expands on way out , you need bigger pm me as I bought some of the dixie molds years ago and they make some large bullets , I can not use them in my rifles .

[jaegerstutzen]

I've been told it is an easy job for a machinist to measure using a "pin gauge", whatever that is. You might need a sizer as well. My mould throws a .578 minie which I size down to .577. I cast a .583 minie for my buddys Zuoave which must be sized to .581. Dial caliper is handy but tough to measure 3 groove, if that is what you have. Good luck.

[Nobade]

Every one of the real PH muskets I've ever measured were dead nuts on .577.

[bedbugbilly]

The problem is, bore sizes can be all over the place on a lot of the repros. I've been shooting rifled muskets for over 55 years and it's always a pain when you get a "new to you" rifled musket and you have to come up with the correct size minie to fit.

As mentioned, pin gauges will work well but then there is the issue of coming up with the ones you need. Slugging a military three groove bore can also be a challenge when it comes to measuring.

I recently purchased a Armisport 1842 .69 caliber "Macon Rifle". I'm in AZ and my tools, etc. ar back in Michigan as far as what I need to get good accurate slugging and measurement. I'm looking at a Moose Mold for a .69 caliber HB semi-wadcutter to use in it as I don't want to throw a 700 plus grain .69 minie down range all the time. So here is how I'm going to determine the size I need. I have a mold to cast a .69 caliber minie - so I will cast one and see how the fit is. Normally, I like a - .002 under the bore size for minie ball - too tight and after multiple shots and fouling build up and it becomes a problem ramming the minie home. If the .69 fits correctly - then easy to measure and order the correct mold. If not, that's where paper comes in.

On your rifle, if you have a minie ball and it is undersize, measure the OD of the minie ball and write it down. On a 3 ring minie, there is enough surface to carefully take a cut strip of paper - depending on how much undersize the minie ball is - tissue paper or even heavier printer paper or a combination of both. Cut a strip about an inch wide and wrap it around the outside of the minie ball - mark it and cut it so when wrapped, the ends come together and don't overlap. Take a glue strip and apply it to one side of the strip and carefully wrap the minie ball from the base up - similar to paper patching the bullet. Gently insert in the muzzle - if you are worried about putting it in too far, carefully drill a hole in the nose and use something like a drywall screws to screw into the nose for a "handle". Ir the paper wrapped minie gies you the correct fit, then carefully measure the OD of the minie on the rings. If it is still too loose, then apply another layer of paper and try again. It might be that you have to start with a layer of something like printer paper and then switch to tissue paper or similar. Eventually build up the OD of the minie with the paper and then once you have the fit you want, measure it carefully. You are working with a hollow base so don't apply so much pressure with you measuring tool (as in if you are using a micrometer) so that you start to deform the hollow base portion or skirt. If you take your time, you should be able to come up with an accurate measurement of what you need.

My Ideal/Lyman 575-213 molds drop right at .575. They are a perfect fit in the Armisport 1855 that I have. The original barrel on the Zouave rifle I bought back in the early 1960s - waaaay too small. I bought a used Zoli Zouave a few years ago and pulled the barrel to exchange with the original barrel on my Zouave. By luck, the bore was perfect for using a .575. The original barrel has thousands of rounds through it from skirmishing and when I get back to MI, I'm going to sed it off for a re-line job.

If you find that your rifle needs a minie ball that has to be sized to your bore, take a look at Lodgewood Mfg. David carries push through sizing dies (much like th eLee push through dies) for various sizes. My Smith carbine seems to shoot best with a .515 slug so I use one of his push through sizers and it works well.

I no longer shoot N-SSA, but it always amazed me that no one has ever made (that I know of) a "stepped" brass gauge that could be inserted in the muzzle of a .58 cal. rifled musket to determine the size of the bore and then the size minie ball required. All the years that I went to Regional and National shoots, I never recall seeing anyone offering one for sale. If someone had the equipment and skill to turn out such a gauge, it seems like they would sell - a .54, .58, .59 version and even something for checking carbine bores.

I don't have any monies cast up or I would be happy to send you some to use to check your bore. If you don't have any available, perhaps somebody on here could send you a few that measured out at .575 that you could check your bore and if undersize, try the paper method of build up. Good luck!

[country gent]

A down and dirty way is find a round pin that barely fits in close is better and a pad of tracing paper or cigarette papers, both these are roughly .001-.002 thick. now try 1 wrap adding wraps until snug and measure with your mikes or do the math if your paper is .0015 1 wrap is .003 dia added to pin dia = bore dia.

This will get you very close with out the special small hole gauges or a small set of inside calipers. For the .570 ish dia a 9/16 dia pin ( 9/16 is .5625. ) may be as close as you get.
Cut your paper in 1 1/2" wide strips and wrap tight around pin. With a known pin size and expected bore dia you can add wraps to close to start. IE with the above and 9/16 pin .562 from .577 is .015 so you could start with 3 wraps of paper. ( .009 + .562 = .571 )

[arcticap]

After a great conversation with Dave951, I now know I really need to measure the diameter of the bore of my Parker Hale Model 1861. Note, I do not have the proper machinist tools to gage this, and need a lower tech method. I can’t find any decent videos on YouTube on how to do this, and can’t find a past discussion or sticky here. I do recall reading someplace that you can drop a heavy piece of brass rod into the barrel, then carefully hammer a soft oversized round ball into a lubricated bore. Then, using gravity, hold the rifle upside down and shake up and down until the brass rod ejects the slug. Has anyone actually done this and had success? Could you do the same thing with some cerrosafe poured into the last few inches of the bore? As always, I appreciate any help and suggestions. Jkrem

This post describe how to slug a bore using Cerrosafe. --->>> https://www.thehighroad.org/index.php?threads/how-to-choose-correct-size.541099/#post-6708238

It's easier to measure when there's an even number of lands and grooves.
And Cerrosafe is reusable.

Cerrosafe can be purchased from Rotometals, instructions are on the product page. --->>> https://www.rotometals.com/chamber-casting-alloy-ingot-aka-low-158-190f/

[carbine]

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[john.k]

The English made Parker Hale barrels were all hammer forged in house.So the possibility of the dimensions being variable is remote.When I see a shooter having problems with Minies,the answer is nearly always too hard bullets that dont upset on firing,usually combined with the wrong lube.(or not enough/or none)

[725]

I've oiled the barrel well, dropped in a foot long brass rod (as big as I can find) and then pounded a pure lead slug into the barrel. Used a rod to further push the slug in 5" or 6". Invert the rifle and bounce the brass rod within to knock out the slug. It's easier than it sounds.