Which Lead round ball Diameter does fit perfectly into an 20 gauge shotshell wad?

TGOFSA,

The way shotgun gauges are determined is by how many lead balls the same diameter as the bore weigh one pound. A lead ball that weighs 1/10 of a pound (1.6 oz) is the diameter of a 10 gauge bore, a lead ball weighs 1/12 of a pound (1.33 ounces) is the diameter of a 12 gauge bore, a lead ball that weighs 1/16 of a pound (1 oz.) is the diameter of a 16 gauge bore, and a lead ball that weight 1/20 of a pound (0.8 ounces) is the diameter of a 20 gauge bore.

Lead has a density of 11.34 grams/cc, a cubic inch is 16.387 cc, so a cubic inch of lead weighs 185.83 grams or 6.5549 ounces. Since we want 0.8 ounces for 20 gauge, we want the diameter of a ball that is 0.8/6.5549 cubic inches, or 0.12205 in³. The volume of a sphere is 4/3πr³, so

0.12205/(4/3π) = r³ = 0.029137

0.029137^(1/3) = 0.307716 = r

So the ball and your 20 gauge bore diameter are twice that or 0.61543"

This is, of course, ideal (excluding rounding error). Actual numbers come from British tables published in the British Proof Act of 1868, and are still used in the U.S. The table numbers are treated as the minimum, and a tolerance of up to +0.020" oversize conforms to the standard.

Code: 
Gauge  Min     Max

 10   0.775"  0.795"
 12   0.725"  0.745"
 16   0.665"  0.685"
 20   0.615"  0.635"

So your 20 gauge will have a bore somewhere in that last range. It may be in the middle, but you should measure it when it arrives, as machining capability improves all the time.
 
The real question is going to be when that solid ball hits the choke at supersonic speeds with a giant splat. Even with a slightly undersized ball with a patch, that's still going to be unpredictable.

There was a design that made pumpkin balls fly straight once. A hole was bored into it and twine was glued into place. The piece of twine stabilized the flight by drag.
 
I have read on som Posts or saw at Youtube that regards contrary opinion of most People, the ROUND eBALL one of the most accurate "bullet" type is. Even in an smooth bore musket.
On the other Hand some say the soldiers equipped around the era of Napoleon marched in lines (hence The Firing Line) in order to hit at least something at 100 Yards. Only at the american civil war as rifled muskets became Standard they were able to hit with the minie or even round ball a target at even 500 Yards.

I wonder how accurate saboted (wad) round balls really are from an smooth bore musket (aka shotgun. A shotgun is nothing else then an modern slide action musket). Saboted round ball and no rifling.

I stopped using the 7/8 oz Lee drive key slug with an modified choke since the wad+slug do not go easy enough through the modified choke. The choke has to be of Improved Cylinder or even skeet according to FortuneCoockie45LC in his Youtube Videos (the wad can determine the pressure. If it goes easy through then it is Ok. If the wad+slug combo has to be forced trough then the choke has to be wider).

My question is which Diameter lead round ball will fit in the 20 ga wad Cup.
 
Depends on the wad cup in your shotgun shell. I have wads here of varying wall thickness.

You may have to make a wooden ball and sand it down until it fits. Then, you'll know for sure. Until you get another brand of ammo or the manufacturer changes the wad, and you'll have to start over.
 
What do you mean with wooden ball and sanding it down? Is that a sort of efemerism?

Yes the argentinian brand generally (12 ga as well 20 ga I realised) have a slightly bigger Diameter (maybe both wad and Shell or the wad is thinner but does not look like that).

I probably just Switch to other brand (spanish ones) which will be tight.

Unfortunatelly sine I am located in Southamerica I can not get wads nor hulls nor 209 primers, nor powder whatsoever.
But that is fine. I am just happy I came as far as I did with my reloading proyect. As I know I am within 400 miles the only one who is here reloading under These circumstances. But local conditions-restrictions are way better than those in Brazil for example (those guys ther they did not even get to bullet casting since they can not get molds in).
 
I think he's suggesting the wooden ball as a gauge to determine what size fits. I don't think it has to be a ball, though. A wood dowel should work.

Nobody will be able to give you an exact answer because of the variation in wads and because of the +0.020" tolerance I mentioned. You'll have to measure this in your own particular gun.
 
On some Forums they had first Hand experience which round ball fits in an 20 ga wad. There is a Standard round ball size which fits almost all wads.
Just I can not recall anymore were I read it.

So I was asking again.

I believe it was .565" or more closely to .575" for 20 ga which fits most wads.

A round ball for an 12 ga already surpasses the weight I can comfortably shoot (in 12 ga the total weight should not be more than 7/8 oz, 382 grains, for me).

If it is a Little loose candle wax can be an viable fix.
 
UPDATE!!

Hi all,

I bought today two spanish brands 20 ga birdshot Shells and tried the .562" Diameter round ball in them.

These .562" round balls are allways a tad loose. Only in the J&G brand they may work fairly well but are on the loose side as well. If you fix 'em with glue or candle wax to the wad then thay will work but how will the Performance be if the round ball is fixed to it's sabot (wad)?

So .562" Diameter round balls are too lose for using as an slug in an 20 ga wad.

The correct Diameter for an lead round ball in an 20 ga Cup (wad) should be .575" or something the like.
 
Again, you can measure it. Get a wood dowel rod the next size larger than you think the ball will need to be. In the U.S., this would be ⅝" (0.625"). I don't know if you use metric or English units in your country. If it is metric, you may be able to buy a 15 mm (0.591") dowel. Take a plastic wad and slip the open end over the dowel. See if it fits into the shotgun muzzle or not. It should not fit. So, you take some coarse sandpaper in one hand and sandwich it over the last inch or two of the dowel and turn the dowel with your other hand and slowly moving in back and forth to gradually narrow it. Stop and put the wad over it and check at the muzzle again. At some point you will make it small enough that the wad over the dowel just slides in through the muzzle where the wad fingers lay over to of the dowel. When it does, measure the dowel diameter. That's the maximum ball size you want.
 
The Wood dowel is new for me. Actually I have no idea what that is.
We do not have here that assortement of stuff you can buy at your Hardware store (or as I was able to in Canada as I was working there).

I guess this .562" round ball will lend itself then well for Buck&Ball loads (George Washington loads) in 20 ga as well as in 12 ga.

I figured putting in one of These 267 grain round ball and stuff on top 4 OO Buck balls for an total of about 470 grains (about 1 1/8 oz).

Any other ideas I can use this .562" Diameter lead round ball for? Any Special shotgun loads?
 
They do settle on that number, but it's based on the wads and having a bore right at the 0.625" middle value of the tolerance range for a 20 ga. If yours were on the tight side, that might be a little snug, but it's a starting point. You probably still want to find a way to measure yours.

Dowel rods are just straight cylindrical lengths of wood. But you can do other things. A simple one would be to take the undersized ball you already have and wrap a strip of paper around it until you add enough thickness for a near slip snug fit into the bore inside a wad. It's just a sort of tubular paper patch. You could measure the paper over top of the ball once you know the number of turns you need, and that would be an ideal ball size, though that's not to say anyone makes a mold that size and that it wouldn't have to be special ordered. But you can shoot the paper tube out with the ball. Wrapping tape around the ball to get a fit is another way to "patch" the ball to make fit for firing.
 
Here my measurements (caliper) of the wad/Cup from inside: 20 gauge #5 birdshot shells

Orbea (argentinian) is .580". In this one the .562" round ball is semi loose.

JG Escopesa (spanish) is .558". In this one the .562" round ball is fairly thight but not tight enough under recoil in my opinion. This would be perfectly tight for the .575".

Rio (spanish brand known in the USA as well) is .589". In this one the .562" round ball is rattle loose. An .575" may be still a bit loose.

I ordered already the Lee .575" round ball mold. I guess the balls will be about .580" in Diameter since Lee molds have a tendency to cast on the bigger side.
 
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