My Renegade likes a .490 ball, .018” pillow ticking patch and 80gr of 3f Goex. A .015” patch had similar results to what you are getting. Now here is where things get interesting. I can only lightly lube one side of the patch with TOW mink oil and the rough side has to be against the ball. When I used more lube and / or lubed both sides of the patch, groups opened up. It likes a spit patch and a dry patch ran between shots because the fowling is pretty great for such a tight patch. I can load a 2nd without a spit patch, but it’s real tight and I didn’t want to deform the ball when seating. But if I clean the barrel with TC’s T-17 solvent and a couple dry patches, I get a flyer on the first shot. Here is my 50yd target. 4 shots. The flyer was a result of cleaning with the T-17 for a new group and I wanted to see if my findings were consistent. They were. The following 3 shots were with a spit patch between shots.
My TC Hawken is proving to like the same right patch, though I haven’t finalized a load. I have only gone up to .015” patch so far in that rifle and get roughly 2” groups at 50. I have a feeling this rifle will want an even tighter patch than the .018” or may prefer a .495” ball with the .018” patch. The .018” ticking patches I’m using are the CVA brand unlubed patches. I’ve read that they actually Mike closer to .022” but I haven’t checked them with my calipers. (Needs new batteries).