With full bore loads in my encore if I dont keep the bullet between 275 and 300 gr my groups will open way up, but at that weight and 100 to 115 gr of 777 I can keep a group out to 200 yards.
I was having this problem 5 or 6 years back so I wrote a letter to TC and these were the weights that they recommended with the rate of twist for my encore and it has worked well for me.
Just my two cents, good luck on the groups and the hunts.

sadly when it comes to shooting full bore conicals, TC is possibly the worse rifle to own for getting the job done with conicals.

Give this a look,
http://www.huntingnet.com/forum/black-powder/324172-t-c-letter-conicals....

Appreciate other suggestion because this seems like a problem with all 1/28 twist loaders. Tell me if I am wrong please!!!
I spent 1/2 hour on the phone this am with a very pleasant and helpful TC tech. The tech said that the omega was designed to shoot sabots ie 1/28 twist. The techi shooters at Tc have develped what they think is the best solution for the conicals. Buy there north western loader with the 1/48 twist. or shoot the following cci 209 primers, 85 grains of 777 powder, 320 maxiball, and use a bore button. The bore button seems to be the mjaor ingredient in this setup. Thoughts? I will let you know my findings on their recommendation.

TC is BSing you badly.

The White Rifle is an old design but it has a 1:24 twist that was MADE for shooting big heavy conicals. Some say its the best conical shooter EVER.

My CVA's ALL shoot conicals, Everything from tc maxi balls - maxi hunters : great plains conicals, thor conicals, powerbelt bullets.

TC likes to turn the other cheek with this issue. Years ago they used to print in the manual telling you that it would shoot both sabots and conicals, they've since changed this.

The Northwest still uses a QLA at the end of the barrel and that is tc's problem.

Will you be hunting deer or elk this year in Colorado? I would suggest picking up some Pyrodex P if you do not have it and either some Winchester W209 primers or Winchester 777 primers. Primers DO make a huge difference in group size.

Now this is my CVA Accura at 100 yards with 150gr American Pioneer Super Stick and the 245gr powerbelts. That is a THREE shot group and guess what, the Accura has a 1:28 twist barrel! So you can copy and send that picture to TC and ask them WHY their competition with the SAME Twist and a QLA set up as well can shoot the lights out at 100 yards with conicals but their TC can not? Ask them how exactly is it they designed the tc barrel to shoot sabots only... is it the rifling depth or the QLA thats the problem?
.403" center to center,

And this is the Accura again but with sabots at 100 yards and 120gr pyrodex rs. 3 shot group with the 300gr hornady xtp. Thats my INDEX FINGER!

Sorry for being so long winded but i am fed up with TC screwing out their customers like this and NOT addressing this problem in their rifles.

And do you remember that picture of my Omega way up above?

Heres what it did at 100 yards with 295gr and 348gr powerbelts with 70gr pyrodex P at 100 yards.

Send TC this picture as well and tell them that they need to get their stories and QLA straight and start taking care of their customers the right way.

FrontierGander, you have a dead ringer for a muzzy. Ever thought about selling to a TC guy?

Actually i sold the omega a couple years back and bought a cva optima. Then i sold that and bought a great plains rifle... LOL i go through so many rifles its not funny.

Frontier we will be hunting elk during the loader season. I went back on my shooting records from 3 years ago when I tested P belts and my accuracy was as good as yours with 100 grains of 777 pellets. Now that I am using powder for the first time the groups are not there. I have not tested P belts. I will try the winchester primers and different powder. Thanks for the ideas.