I have a Sidekick with a Williams receiver sight and it shoots clover leaf groups at 50 yards, which is further than I can see on my stand.
I cast a 300 grain bullet 45 caliber bullet for the 45 Colt from Lee Precision mould and load it in an MMP 3 petal sabot over 100 grains of Triple Seven using Triple Seven primers and it does shoot very cleanly. Regular shotgun primers leave a big mess. This load is about 1750 fps. The Federal 45-70 300 grain load list velocity at 1800, so we are in 45-70 territory. It has " noticeable" recoil.
The breech plug screws out using a big screw driver provided with the rifle.
There's a lot of good muzzleloader info at
www.randywakeman.com. Check for the MMP 3 petal sabot under "inline muzzleloading. It loads much easier than the common 4 petal.
This is a 50 cal rifle with a 28" twist for conical projectiles, but does okay with patched balls.
Hope this is helpful.