Elk, modern inlines, and conicals
 

Ok, I am new here but not new with muzzleloaders. I have 3 traditional Hawkens(2 TC, 1 Pedersoli)several inlines(White Bison, CVA Optima, Knight Wolverine) All are open sights as I mainly use for elk in Colorado. Actually only used the TC Hawken in Colorado. I am getting good results from it using 450 gr cast bullets I made.
My question is as far as the modern inlines that most have the 1 in 28 twist. Is there anyone shooting conicals out of the modern inline and getting good accuracy at 100 yards? If so, what rifle, load and bullet? If you cast it yourself what is the band width? I did a lot of experimenting last year with the White and Optima and never could get anything to my satisfaction. The TC Hawken with the 1:48 twist most claim is not that accurate with the conicals. My results are the opposite. The Hawken out shoots the inlines. Maybe the longer barrel and longer sighting plane is why.

I shoot 45 Cal White ML with either a 350 or 465 grain conicals with great accuracy. My 45's have a bore size of .451. I like to size my concials to 451.5. This helps ensures they will not move off the charge yet still allow you to easily push them down the bbl with one hand. I also found that a felt wad helps a little to squeeze a little more accuracy out of them. If you are having issues with Open sights, maybe try using a Peep Sight.

I got the Lyman peep from Doc and mounted a globe front. Using 6:00 hold. I tried No Excuse 450 or 460s that are slip fit. And various other conicals. Started out with a scope to get a load developed. Took it off as it was the wrong mounts and was banging my forehead. I'm going to try the wads. Mine is 504. Any particular wad I should try?

1:48 twist is very accurate with 400+ grain conicals. Could be the other inlines have deeper rifling and your conical is not sealing up as well as it needs. Try a wad and see how that improves.