At least not for now. Today I took the Lyman flinter back out to try Lemoyne's suggestion of using .535" balls.
Here's how it went today. Each load was shot at 50 yds using 100 gr of Goex FFFg, spit patch between shots and a thorough cleaning of the bore with T/C #17 between each group.
Group 1: Base line .530" ball/.020" Oxyoke prelubed patch
Group 2: .535" ball/.015" Oxyoke prelubed patch
Group 3: .535" ball/.018" Pillow tick liquid wrench lube
Group 4: .535" ball/.015" Oxyoke/ 100 gr Goex FFg
Results: Groups 1, 2, and 3 all came in at 1.5" for 3 shots (+/- a couple thousands). Group 4 with the FFg measured 1.9".
The .535"/.018" combo was a real bear to start down the bore. (Wish I would have had Semi's mallet). I did note that the FFg had more of an ignition delay than the FFFg.
Now I don't know if it make a difference or not but the .535" balls did have a larger spue cut tit than the .530"s that I had cast. I did make an effort to be sure this was pointed straight up when I started the ball.
So I guess for now I am just going to have to shoot the crap out of that barrel and get a couple hundred shots through it before I get serious. But even now, its definately a 75 yd deer buster for sure.

I used to have a .535 mold and made a lot of ball once. When I tried to load them in my Renegade with a .015 patch I had to beat them down the barrel. I shot two of them. And after that used the couple hundred I made as sling shot ammo. Which by the way they worked really good for. I ended up selling that mold to Semisane I think it was. But he then made some ball out of it (beautiful job) and they do load in my Lyman Trade rifle. They are tight, but I can load them.

Although the kind of groups you are shooting are more then acceptable. In fact I would be down right tickled to death with them.

I don't like to look at bad groups for a 100+ shots. I gave my old GPR a good number JB strokes before ever shooting it. It loaded smooth, and shot good groups right from the beginning.

I used a .490 ball, .018 pillow ticking patch, mink oil lube, 85 gr of Goex 2f, 4f in the pan.

The same thing for the .54 I had, except .530 ball.

Muley - this sucker doesn't like light loads. I am shooting best with 100 gr of FFFg. I really don't want to push past that. But even with this load, the recoil is really moderate.
I probably only have about 50 shots thru it right now.

None of mine liked loads lower than 100gr 3f either. 110-120gr 3f always shot the best for me at 100 yards.

I just looked through my .54 GP target file and was really surprised to find that I've never shot over 95 grains of GOEX FFFg out of it. And that load shot better than any of the lighter loads. Most of the five-shot 50 yard groups are under 1.5". The 100 yard groups are around 4". I wonder if a stiffer load would tighten the 100 yard groups.

Semi - looks like you're going to be making a range trip with the GPR shortly?!?!

That's weird. That was my most accurate target load that I was going to use at shoots.

Pretty much what Dutch says should be an accurate load too.

My enthusiasm for range trips has been greatly diminished by the hot weather. But I might tough it out in the next few weeks.

Our temps are perfect, but it's always windy. I wanted to sight in my peep sight today, but I hate doing it in the wind.

It's suppose to be calm at dawn tomorrow, so i'm going early.