Re: 18 inch group with flinter
Griswold has made a very valid point. I agree with his suggestion, start close, 25 yrds, if need be then work out from there.
Getting used to the flash and then shot, takes some practice.
Enjoy yourself there, experiment with different loads, such as grains, start low, then work your way up.
I shoot 70 grs. black powder in mine with a patch and rd. ball. You may like something different. Your gun will eventually tell you what it likes. And you will be really surprised of the groups you can shoot when all comes together.