Now I know why they call them roundball barrels. Just for poops and giggles I took my GPR Flintlock out with some sabots (300 gr Nosler Partition, 340 gr Dead Centers, 300 gr Hornady SST's) 100 gr 2F Goex.
5 shots each and my best group at 50 yds was as wide as the paper I was shooting at. (8 1/2 x 11). I had to adjust the peep up by eight clicks just to get them on the paper. With the roundball sight setting I was hitting the ground 3 feet in front of my target. I returned the peep back to it's original setting but up one click (becuase I was a little low before) and let fly with a .495 and it was bang on.
Now I know, but I just had to seefor myself.

try different conicals. i know my kentucky flintlock will shoot powerbelts with the 1:66 twist.

I've never had any luck shooting anything but roundball out of the slow twist barrels. I have three of them and while they are deadly with roundball, they stink with anything else. Never underestimate the power of a roundball. Have fun shooting.

I seen short conicals shoot excellent out of RB barrel,but you may have to reduce the charge a little.
I have a early t/c 45 cal. flinter barrel with a 1in 48 twist,funny thing it will tack drive RB but will not shoot a conical to say it life.STRANGE

I have some 240 grpowerbelts, 355 TC Maxi hunters and some 240 gr xtp's yet to try out, but I'm not holding my breath on them after seeing what went on today. I'm sure the 495 ball will do the job but I was curious about the sabot's. I'll give them a crack tomorrow if it isn't snowing again. We got six inches yesterday.[:@]

Well you keep the snow up there. I have had my fill of snow and cold. The warmth today was welcome.

I find this real interesting all the different loads you are trying out of that rifle. Thanks for doing this.

Well, cayugad, you got me interested in moose with a flintlock. I was curious how the heavier bullets would work out of the GPR. I'll try the rest of them out to see how things go. I havesome 240 grpowerbelts, 240 xtp's and some 355 TC Maxi Hunters yet to try. I don't think either of them are decent moose medicine. If the TC MaxiHunters shoot ok then I'll get some TC MaxiBalls to see if they shoot well. After all that, I'll steal myDeerStalker back from my young fella and do it all over again. I already know what I would use in the Omega (209 Win Primer, 2x50 gr T7 Pellets, 340 gr PR Dead Center), but if I can get some decent groups with a flinter with the heavier bullets, I would take it moose hunting this fall. I know that a ball would do it, but I would feel more comfortable with a bigger piece of lead in the tube for moose. Deer, roundball all the way this year.

Lonewolf,
I've read an article on what twist will stabalize a particular length of projectile. If I recall it has to be about a .5 inch bulletfor a 1:60 twist barrel in .50 cal. Which is basiclly a ball. I'm going to see if I can get some of the Buffalo Bullet Co. Ballets to see how they shoot as well as some Keith UL1 from PR Bullets. I'm open to all possibilities if they will shoot well and if "I" think they will perform on larger game. I have no doubt that a 240 gr powerbelt or xtp are not good enough for moose, but they would be ok for deer if I chose them for that (But it will be RB for deer for me). Geez I just remembered that I have some 250 gr Nosler Partitions to try as well.

Will it ever end???????

I think the Buffalo Bullet Ballets or Hornady PA Hunter conical is 1/2 ball 1/2 conical now here a bullet for slow twist barrels ,I think there are 240 grainers