Patch thickness ?

[Sunbeam]

Hello,

I have a 16 gauge smoothbore flintlock musket that measures 0.667" at the muzzle with a digital caliper

I had the barrel re-proofed in UK last month and I'm in the process now of doing it all up, work on it is now coming to an end and I am now buying a ball mould.

After placing my order for a mould last night, I woke up this morning having second thoughts about the size I ordered. My Hawken is 50 cal and shoots a patched 490 round ball with a 0.012" patch. It needs a bit of a whack with a ball starter and a little shove with the rod to get going, but then it's OK, accuracy is great

I intended to use 0.018" pillow ticking for this smoothbore musket as I can get LOADS of it locally and it is consistent. The ball mould seller says:-

"Patches
If you are using a patch, the deduct the thickness of the patch from the mould size. E.g. if you want a .750″ mould and will be using a 15 thou patch, you would want to order a .735″ mould."

"Shrinkage
The next thing to consider is the shrinkage. You can use this simple formula to calculate the cavity diameter: Multiply the ball diameter with 1.005 to get the size of the cavity. This is based on Wheel Weigh alloy with 0.5% shrinkage. For a softer alloy you may increase the factor to 1.007 (0.7%).

These two factors should give you everything to calculate the size mould you need."

So with a bore of 0.667 (16 Gauge) and a patch thickness of 0.018" and times by 1.007 as I'm using soft lead, I got a number of 0.653" and that's what I ordered.

But now I'm thinking I don't really want to be ramming balls down this musket as accuracy is unlikely to as good as the Hawken, so what's the point in hurting my hand for a bad group? I'm only ever going to be shooting 25m Target anyway. I do want to get the best group I can as our club is a performance target club. Also the seller suggested an 0.018" patch was quite thin.

Does anybody know what allowances I should be making for working out what mould I need to buy?
Each mould is £33 ($41) so don't really want to get it wrong.
I'm now thinking of -0.030" x1.007 and adjusting the patch rather than the 0.653 I ordered ????????
The seller is holding back my order until I decide.

Thanks.

 

[Grenadier1758]

Use the 0.012" thick patch you use in your 50 caliber Hawken. Or use the 0.653 ball with wadding. Get a ball of jute twine and fray the twine to a ball big enough to nestle the ball in the muzzle. It should be loose enough to load. Put an over shot card over the ball if you are concerned about holding the ball in place. As you opined, the accuracy of the smooth bore won't be as precise as your rifle, so patch thickness isn't really that precise a calculation.

Note: There is no mathematical formula that can be applied to the calculation of ball size to patch thickness that will result in an absolute best selection.

These concerns about ball size are one of the reasons we recommend that you order balls of the approximate size and find the size that works best..

 

[hanshi]

Since smoothbores lack the grooves for the patch to compress in a smaller ball dia. and thinner patch - compared to a rifle - are usually recommended. For my use, mostly, a rifle ball .010" under bore diameter and a patch around .018" to .024" works for my rifle-guns. A smoothbore often likes a ball .015" to .020" under bore dia. and a thinner patch; the .012" patch suggested by Grenadier sounds like a good start.

 

[Sunbeam]

Thank you.
I went with the size the seller suggested which is inline with what you guys are saying

 

[tenngun]

You might want to get several balls to try. I have a .62 and shoot both a .595, with patch or a .600 nested in to a wad. But.... the .595 can shoot well with a wad and I can use a thinner patch in the .600.
Then I’ve made cartridges for it with a .570 ball. It would still turn Bambi French but not-shooting so well as a tighter load.

 

[rich pierce]

Get a mold or some balls 0.020” to 0.030” undersized then use various patch thicknesses till you get an intact patch.

My new .690 is shooting .662 balls with a 0.020” thick patch. As said above the math does not work. I can start these balls with the butt of a knife and they ram nicely. Patches perfectly intact. Still working up a load but hitting beer coasters at 25 yards and at 75 yards keeping them in a frisbee sized circle. Accuracy seems to fall off between 50 and 75 yards.

 

[Loyalist Dave]

NO PATCH!

So the problem with a patch is a) it's not documented for the time period, and b) the reason for that may be that as many folks that shoot round ball in smooth bores have reported, the patched ball is less accurate than a very large round ball.

In a rifle barrel the grooves impart a spin to the bullet, true, but they also cause the patch around the ball to fold in a very similar and uniform pattern each time a ball is loaded. In a smooth bore the patch folds a different way each and every time, which makes for an inconsistent positioning of the ball in the barrel each time.

So if you're not going to put the ball in a uniformly rolled cylinder of paper, then another option would be to use a ball that is .650 in your 16 gauge.

LD

 

[Greenjoytj]

I would think that the compromise between ball diameter and patch thickness would be to still have the ball to show a thin band of cloth weave marks embossed into the ball. The width of the cloth marks will also define the effort required to start the PRB into the bore. I usually use a small light 8 ounce dead blow hammer on the ball starter tool to save wear and tear on my fist.
I still want a fairly snug fit to reduce gas blow by as much as possible within the PRB fitment compromise.
Also a felt over powder wad helps to reduce blow by and patch burn through particularly with thin patches.

 

[tenngun]

Blow by will reduce the power of your shot. But is it all bad?
Many old powder charges seem large compared to what we might shoot today. Some of the reason is much powder was low grade.
Recorded Bess loads are from fifty to twenty five loads to a pound. 140-280 grains.
On his you tube vids Duelist 54 shoots larger charges then I do inhis .62. And gets pretty good accuracy from bare ball. Why?
Gas blowing around the ball is going to provide an aerodynamic cushion around the ball, holding it in the center of the bore.
Is this the best answer? Maybe, but boys can get groups from PRB in smoothies.
Is it not historic? It’s not mentioned in seventeenth and eighteenth century loading manuals, but we have leather patches written about in 1847 ( in the form finger tips from worn out kid skin gloves) this writer didn’t claim inventing the practice so we can assume it was done for some period of time before 1847.

 

[ugly old guy]

0.667 inch bore diameter at the muzzle?
What is it at 6 and 12 inches down the bore and at the breach?
The barrel may have a choke.
16 guage is a shotgun bore. Shotguns, even black powder ones loaded from the muzzle, usually have a choke.
Depending on the age of your arm, the bore may have a choke taper from the breach to the muzzle.

 

[Sunbeam]

0.667 inch bore diameter at the muzzle?
What is it at 6 and 12 inches down the bore and at the breach?
The barrel may have a choke.
16 guage is a shotgun bore. Shotguns, even black powder ones loaded from the muzzle, usually have a choke.
Depending on the age of your arm, the bore may have a choke taper from the breach to the muzzle.

Thanks, I will check first thing in the morning, it's not too late for the ball mould.

 

[Sunbeam]

Just checked, all good, .667 all the way down.
I turned up a snug fitting brass plug and carefully feed it down, consistent resistance all the way.

 

[Grenadier1758]

The muzzleloading shotguns historically were cylinder bores. No choking. Sunbeam, you have a 16 gauge smooth bore fowler. Of course you can shoot round ball and being cylinder bore there will be smooth loading whether you use wadding or patches. You have a wide tolerance of acceptable ball sizes.

 

[Sunbeam]

The muzzleloading shotguns historically were cylinder bores. No choking. Sunbeam, you have a 16 gauge smooth bore fowler. Of course you can shoot round ball and being cylinder bore there will be smooth loading whether you use wadding or patches. You have a wide tolerance of acceptable ball sizes.

Great news, thank you.

I have a range of firearms, but this is the first musket I've owned (not going to be the last). It's very hard to own firearms in the UK, and the hoops we have to jump thorough are over the top. I have personally found that the information people have here is mostly kept to them selfs or they simply don't know and they just fumble their way through with no real accuracy. So I am very grateful for your help, I wish I could live in the US, My black powder collection would be huge if I did


My club are not as helpful as one would like, so I'm kinda on my own with working her out. When I got the musket, it was all there and working, but somebody had clearly 'had a go' at cleaning her up to sell. So parts were not so good, I asked my club what I should do. The answer was stoke her up and fire. I didn't think that was a good idea as I was not SURE the barrel could take it considering the quality of the 'restoration'!

The barrel had a Liege proof on it so clearly had not been re-proofed since being shipped into the UK. I decided to send the barrel to Birmingham UK for a new proof. That was done and she passed, so I was able to get on with the full strip down and tidy up. I have a thread running on that here already.

Now the work is almost finished and I'll be staining and finishing the stock this week, I thought it was the right time to order the ball mould as the project is now fully viable with a proofed safe barrel and finished lock and stock (at least as far as the hard work).

So thank you guys for your help

 

[Grenadier1758]

Check with Britsmoothy as I seem to recall that the UK has restrictions on shooting ball from a smoothbore. Your club should so be aware of any restrictions. The restrictions may apply to multiple ball of large shot size or buck and ball loads.

 

[Sunbeam]

The restrictions are 75cal max and no buck, as we are a paper target only club.

 

[Flintandsteel]

Usual starting place for a smoothbore is a pure lead ball, .020 under bore size, and patching to fit for accuracy.
For my smoothie, bore is .615.
A .595 ball and .020 patch loads easily, and very accurate.