First, welcome to the site!! Muzzleloaders can and will fustrate the heck out of you and then when you think you have it all figured out, your frustrated again. So lets start back from the beginning. Let's pretend you just bought it. What are you going to do with your new muzzleloader?? First you want to clean it and I mean clean the heck out of it. Process 1. Start a pan of water on the stove and get it boiling hot!! While that is happening you want to start cleaning it with a brass wire brush, scrub it hard. Then use the hot boiling water and pour it down the barrel. You want it so hot you can't touch the barrel with out an oven mit. Then scrub the heck out of it again. Then start running dry patches followed by some patches with a good oil. You can use RemOil or something. (most people won't recommend RemOil however it will work) Then let it cool for a while and then repeat the patch process. Dry then a very light amount of oil. Then let it cool. Now your barrel is clean. Your barrel comes from the factory with a ton of grease and oil to prevent it from rusting. Get it out of there, it causes your loss of accuracy. Either way your barrel is clean now and ready to shoot, but hold on lets make sure your ready to shoot first.
Now Process 2 lets make sure you mounted your scope on correctly (this is where I thought I was doing it right however I wasn't). If you did NOT loc tight your bases on this is where your problem is. You can use finger nail polish but you want to loc tight your base on. This is a must, muzzleloaders have a funny recoil and it will knock your scope off.
Now Process 3, GET RID OF YOUR WHITE HOT!!! You want to use Blackhorn 209 or Tripple Seven Powder (FFF). If you buy tripple seven u want to use tripple seven primers. I RECOMMEND Blackhorn 209 and hornady sst 250 grain or Thompson Center Shockwaves 200 grain.
Now the rest is very easy go shoot. Make sure you do the exact same process when you load every time. If you buy Tripple Seven Powder you want to clean between shots one wet patch and a few dry patches. Pour powder in tap your gun a little to make sure powder is settled. PUSH the bullet down till it hits the powder then a firm push down to make sure it is snug. (One thing if you use aerotips you want to get a jag designed to push the aerotips down).
The process you use to load your muzzleloader should be the exact same everytime you load your gun. You should see your groups shrink up. IF not there is some other things you can do but lets start here.
One last thing, try this sight out Modern Muzzleloader
there is a lot of people on here who have helped me achieve accuracy out to 300 yards when I couldn't get a group out of my cheap Winchester Apex, which I almost threw away!! You can spend a lot of money trying different things out but when you get onto a site where it is nothing but muzzleloader and people who do nothing but muzzleloader, helps out a ton.
Good Luck and let us know how you do.