OK, first, there is a difference between mini balls and Minié balls: mini balls do not exist... or if they do exist, they wouldn't work in your gun and if you use the prefex "mini" it would imply that the balls are smaller than normal. Minié balls were designed by Claude-Etienne Minié and are basically a hollow-base rifle bullet with an expanding skirt. They do not use patches. They are a type of conical bullet.
So, from the context of the post, I gather that you are using patched round balls, often abbreviated as "PRB". There are a number of things that could be hurting your accuracy. Changing patches certainly could make a difference. Most PRB shooters recommend tight patches, typically a .490 round ball with a .015" thick patch. Some even go with an .018" or .020" patch. I have not found that to be the case and get acceptable accuracy using scrap linen, used pillow ticking and even silk cut from an old silk pillow case... but I am not really a precision shooter. If you need to keep a hammer in your possibles bag, then something is wrong.
You don't say what kind of powder you are using, but you should not absolutely NEED to swab the bore every three shots with only a 65 grain charge. If your patches were previously pre-lubed, then they were likely lubed with T/C Bore Butter or something very much like it. That product gets a bad rap around here, but lots of people (myself included) use it regularly.
You are shooting a flintlock, which opens a whole 'nother can o' worms. Are you experiencing hang-fires? Is your flint wearing out and not sparking as well as it used to? How much powder do you prime the pan with? What kind of powder do you prime with?
The secret of accuracy and reliability with any gun is consistency. Do everything you do the exact same way and you will generally have the same results each time. Change some variable in the equation and you will have a different result than you did before.
Go back to doing what you used to do when you got acceptable accuracy. That may help. If it does, stick with what works, if not, then listen to the advice given by the other gray beards who inhabit this domain.
Good luck!
So, from the context of the post, I gather that you are using patched round balls, often abbreviated as "PRB". There are a number of things that could be hurting your accuracy. Changing patches certainly could make a difference. Most PRB shooters recommend tight patches, typically a .490 round ball with a .015" thick patch. Some even go with an .018" or .020" patch. I have not found that to be the case and get acceptable accuracy using scrap linen, used pillow ticking and even silk cut from an old silk pillow case... but I am not really a precision shooter. If you need to keep a hammer in your possibles bag, then something is wrong.
You don't say what kind of powder you are using, but you should not absolutely NEED to swab the bore every three shots with only a 65 grain charge. If your patches were previously pre-lubed, then they were likely lubed with T/C Bore Butter or something very much like it. That product gets a bad rap around here, but lots of people (myself included) use it regularly.
You are shooting a flintlock, which opens a whole 'nother can o' worms. Are you experiencing hang-fires? Is your flint wearing out and not sparking as well as it used to? How much powder do you prime the pan with? What kind of powder do you prime with?
The secret of accuracy and reliability with any gun is consistency. Do everything you do the exact same way and you will generally have the same results each time. Change some variable in the equation and you will have a different result than you did before.
Go back to doing what you used to do when you got acceptable accuracy. That may help. If it does, stick with what works, if not, then listen to the advice given by the other gray beards who inhabit this domain.
Good luck!