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Pitiful 20 ga roundball accuracy

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Tried .600 balls in a .620 bore, with a 0.015 wet patch. 70 grains of FFG. I got 3 or 4” groups at 20 yards. This is with a rear sight. Very disappointing. This is in a 1” octagon, 32” Green Mountain barrel, percussion gun.

I can’t think about using a tighter load. This loaded ok but needed swabbing between shots. Patches were not blown.
 
Rich Pierce said:
I can’t think about using a tighter load. This loaded ok but needed swabbing between shots. Patches were not blown.

Not sure I understand, Rich.

Do you mean you don't want to use a tighter load because you don't want to have to swab more between shots?

Gus
 
Rich Pierce said:
This is in a 1” octagon, 32” Green Mountain barrel, percussion gun.

If that's a GM drop-in like mine, it's actually a little under .620 if you haven't measured it. Mine shoots best with a .595 ball and l018 ticking lubed with grase (mink oil tallow from TOW). Each gun is a little different for sure, but mine is what it is.
 
Gus, I’m not sure it will load tighter. I don’t have experience with round ball in smoothbores. I guess I worry there’s nowhere for the fouling to go (no grooves). I figured if the patches are not blown, I must be ok.

I will try 0.018 patching tomorrow.

Brown Bear, it’s pre-drop in’s. I will try grease tomorrow too.
 
Assuming you are shooting a smoothbore, that IS disappointing. Your groups should be half that size.

Are you sure the barrel is inletted and pinned in properly with no stress points? Including the tang?

Eliminating the possibility of the above-mentioned possibilities, just for kicks, try bare balls with various kinds of wadding/wads.

Kind of a shame that you may not be able to accurately shoot patched balls out of a Green Mountain barrel, though.
 
Rich Pierce said:
Gus, I’m not sure it will load tighter. I don’t have experience with round ball in smoothbores. I guess I worry there’s nowhere for the fouling to go (no grooves). I figured if the patches are not blown, I must be ok.

I will try 0.018 patching tomorrow.

Brown Bear, it’s pre-drop in’s. I will try grease tomorrow too.

Hi Rich,

My accuracy load in a .753" diameter Brown Bess was a .735" ball (the largest mold size then available) and a thick ticking patch with 70 grains of FFg powder. I originally used a greased patch, but found I needed a spit patch in the warmer to hot months, or else I couldn't get the ball down without a thorough swabbing. I don't think I ever shot more than 7 times in a row in any match and didn't have a problem with not swabbing between shots for that many rounds.

I have been particularly intrigued with the loading method George has mentioned for very good accuracy out to and just over 100 yards with his smoothbore. I might be mistaken, but I think he uses an over the powder card, then a fiber wad and then a patched round ball. The fiber wad may cushion the propellent gas push against the PRB in the bore and thus make it more accurate.

I know if I were working up a load for a smoothbore today, I would try Spence's recommendation with the additional over the powder card and cushion wad.

Gus
 
All my smooth bores won't shoot unless a wad is betwixt powder and ball. I use grease and don't swab.
I have also never done any good if the barrel is pressing on the lock!

B.
 
How much powder are you shooting, when I got my first smoothie the recommended charge was 80 grains, I went to 75 and groups didn’t improve. They didn’t get better at 90 so I stayed at 80.
Then I read on the forum here of guys shooting 60 to 70, I tried some lower and bingo, found 65 to do real well.
Do you have a rear sight? That won’t shrink your groups but I find it a lot easier to aim.
 
juice jaws said:
Britsmoothy said:
All my smooth bores won't shoot unless a wad is betwixt powder and ball. I use grease and don't swab.
I have also never done any good if the barrel is pressing on the lock!

B.
Brit, do you also use a patch ball over the powder wad?
My .45 it makes no difference if I use a patch or not but then the balls I have are .440 and .445, the later being better.
Pretty much all my .58" bores I had and using a .562 needed a patch but again with a wad.
I find it depends not on tightness but a snug ball fit and the use of a wad.
My .63 however shoots a .600 well with a wad but then again it will also shoot a .562 with wad and three, yes three patches!
Just got to fool around.

I don't wish to sound like an expert as I am not and I shoot more shot than ball.
I do have opinions on the subject however.
Shooting a target will most often with a smoothbore look, when one is use to seeing targets shot at with a rifle often be disappointing!
Keeps things in perspective, a ball from a smooth bore is a short range hunting gun.

Another thing I found with large balls is they can suffer from their own mass, they can obturate too much in the barrel. Smaller ball don't seem to suffer as bad from this.
There are so many variables, especially internal things it can seem like a mine field.

Irrespective of ball size and patch combo without sufficient wadding some gas passing the ball will happen. No matter how tiny this amount may be it will be a random act every shot and just enough to open a group.
Depending on gun, any drum or nipple bolster pressing on a lock plate will upset things.
Double barrels often make a good combination gun, I mean just stick to the one favoured barrel for ball.
Also watch that a barrel is not bearing down on a mainspring, just touching something other than wood will upset things.
B.
 
Britsmoothy said:
All my smooth bores won't shoot unless a wad is betwixt powder and ball. I use grease and don't swab.

That was my immediate reaction, though fortunately I've never needed a wad in addition to the right patch.

I can't cite any statistics, but I recall that lots of folks here report needing a fouling shot before their smoothbores settle down and group. Using the grease and a tight patch/ball combo that fairly scrubs the bore with each loading, I've never needed the fouling shot for groups.

BTW- My GM barrel is producing 25 yard groups on the order of 1-2" no matter what powder charge I use. I can't mix and match a bunch of powder charges to get that kind of grouping, but long as each charge in a string is close to the same the groups are consistent.

Bottom line, when the right patch/ball/lube combo is hit upon, decent groups are kind of a no-brainer.
 
BillinOregon said:
Hope you get this sorted Rich. Eager to hear what worked.

Well boys, I won the smoothbore match today! I upped the charge to 80 grains, used a graded cushion was the 0.018 grease patch with the .600 ball. Balls pretty much went where I aimed.

Thanks for the great help!
 
Pretty good sign you're dialed in now! Well done on that AND the win. Most matches it's more about the critter behind the gun than about the gun. Nice when they both come together.
 
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