What kind of shot cup could improve my shotgun pattern? I have a 20 gauge flintlock. Its loaded the standard way but the pattern isn't so hot. At twenty yards its pretty good. I would like to get it a little tighter for at least a 30 yard shot. I am using an ounce of copper plated #6 shot with an equal volume of 3f black powder.
If you're using relatively modern manufactured Lawrence brand copper plated shot, instead of the high quality original Winchester Lubaloy copper plated shot, my experience is that its junk...normal hard magnum lead #6s patterned better than the Lawerence brand copper plated shot because they went cheap and instead of plating chilled shot, they just used cheap soft lead with a copper colored wash, not plated at all.
By contrast, Ballistics Products Nickel Plated #6s tightened the pattern up some compared to hard magnum lead shot. And if your interest is in turkey hunting you can use a lot more shot than you're using...a long shot string is a good thing for a tiny stationary target like a turkey head.
Some folks are locked into a mindset that BP smoothbores must be loaded exactly like a modern equivalent gauge and to each their own of course, but it simply isn't a requirement in the muzzleloading smoothbore world