I'm just being completely honest about my group size Dan. Perhaps we're describing our groups in different ways. When I say 3 or 4 inches at 100, that's what I can demonstrate on demand (in good conditions) on any given day with open sights for 10 shots. About 80% of those shots will be in half that group size. I have shot some that are just slightly larger than 2", but on average I can produce 3 to 4. The best bench shooters at Friendship using peep sights and 40 lb guns cant demonstrate 1" groups with boring regularity. They "can" do it but cant always do it. But anyway, if there is something I have overlooked in my load testing, I don't know what it might be. Last year I sent about 6000 roundballs downrange, a lot of that in testing off a bench, and what I do know for a fact is that something besides wind is blowing mine and several other roundball shooters' groups between 100 and 200 yards. The article about twist seems kinda far fetched to me too, but after messing with black powder for 40 years, I'm reluctant to pronounce something "BS" until I've tried it. Like I said before though, I'm just not ready to invest in another barrel to satisfy my curiosity. My plan at present for the 200yd musket target is to use a paper patched minne. Maybe I can get that down to 4moa. We'll see.
I have difficulty out here shooting small groups almost any time.
This is a composite of 2 targets at 100 yards shot against picket rifles with my open sighted flintlock. It took second and I was shooting against picket rifles with more elaborate sights. But round ball guns placed 1 and 2 but the leading picket rifle only lost because he misread the wind on 1 or 2 shots... We routinely shoot on days when the backstops need to be weighted with heavy chunks of steel to keep them up and they sometimes blow over anyway. But if we called the match for a 15-30 mph wind we would not shoot 1/2 the time. Shooters from the east have no idea for the most part.
Current wind here is listed on Wunderground as 21 gusts to 34.... If its match day in Cody I go shoot. We have only called one match at 5 shots and it was too windy to keep any targets up. Probably gusts to 60 or so.
I shot four 3 shot groups at 400 yards with a modern CF with bullets near .600 BC that averaged 1.95" while getting a zero for the distance. I shot a 5th with another load that was about 2". I get to the match, set the scope for 400 and the first shot is 3.5" low.(?) The next 4 are strung horizontally about 3" but good elevation the VERTICAL dispersion was about 1". I won the 400 yard stage on centers (1) anyway... Things seldom go as well on match day as one would want.
200 yard with a 22 RF is also enlightening.
There is an excellent chance that you are getting wind induced dispersions that you are not noting as wind related. OR YOU NEED MORE POWDER. I hesitate to say this since I have no idea how well your guns are put together but this is often a factor. I have had 54s that would not shoot with less than 120 gr of FFF.
Even with a HV 50 cal (109-120 gr of FF Swiss) a puff of wind can put a bullet out an inch at 60 yards 180 degree shift can change the point of impact 4-5" easily from previous shots. There are all sorts of effects that the wind has on bullets that the RB shooters never encounter since the ranges are too short.
Wind drift is based on how much TIME the bullet loses from launch to impact, I have read. The higher the BC the less velocity loss the less wind drift.
Go to a ballistic calc web site and run a .070 BC at 1900 then a .350 BC bullet at 1350 and see what the deflection is. Then run a .600 at 2800 and see what it does.
A puff of wind that is totally unnoticed with FLAGS will move a ball a foot at 200. Do you understand mirage and how to read it? 200 is a different world. With heat and no wind the mirage will "boil" with a light wind it can move the apparent target at a 45 from its actual location.
I once had a 50 caliber ball drift completely off the butt of a deer. By about a foot at less that 150 yards, about 4 ft of drift. I had no wind where I was standing that would cause me any trouble. But there was a wind blowing up the deep gully (for you easterners) I was shooting across. I found this out after the shot when I continued my walk back to the ranch house and it nearly blew my hat off in 20 yards. I was not paying proper attention.
So unless you add some wind flags and learn to USE them there is little chance that you will get groups at 200 that are only 3-4 times the size you shoot at 100. THEN there is the sighting problem. PUT A TANG MOUNTED PEEP SIGHT ON or a scope. See if this helps.
But as I pointed out any wind will blow the group at 200 and can effect the vertical as well. Though the slower twist in RB rifles is not so prone to this as faster twists.
Do your homework, look into wind and mirage. Get some wind flags. REALLY wring the rifle out at 100 to see what it will REALLY do. Round balls are not going to suddenly become unstable at 150-200. The rotational velocity will not bleed off like the initial velocity does since there is far less drag. So while the velocity will fall off rapidly the ball will still be spinning fast enough to keep it stable.
I goofed earlier and did not get the photos posted properly
This one in particular
Dan
