I sold my 120 a while ago...When I first started with it I tried a lot of things.... It was very frustrating!!
The 500gr bullets I had cast from WW's, with a full case of Goex 2ff, tumbled supper bad if the bore was fouled at all. You could hear them tumbleing through the air...it was a really eirie sound
I tried about everything and found that a 550gr 20:1 SPG lubed bullet shot very well. But it was more work to load and expensive since I bought the 550's comercially...and the 120 will eat a lot of powder.
Since I wasn't competeing with it, and just wanted it to shoot without a lot of fuss, I found a load I could shoot all day and never even worry about the fouling.
The load was 70gr 2ff Goex lit-off by a 10gr Unique kicker, a thin cardboard wad (punched from a Hornady bullet box) pushed down on the powder with a wood dowel, and a stack of felt wads to the base of the bullet. This combination seemed to shoot anything well. I even used 1000's of the very hard-cast 500gr LaserCast slugs with the crayon lube with good success. This load would go into 1" at 100 off the bench and printed around 12" on the steel buffalo at 500yrds off the x-sticks.
I let a friend shoot it off the bench one time at 100yrds. (with the Laser Cast 500gr). His first shot was about 1/2" outside of the bull...he shot two more shots and everyone started teasing him because they all thought he was missing the target completely because throught the scope you could see that there was still only one hole in the target.
I reached over and gave the windage knob a litte turn on the Venier and his next shot drilled the blue thumb tack that I had stuck in the center of the X...Little shards of blue plastic were stuck in the target backer.
But the big Quigley rifle was just to heavy for packing and hunting, so I went back to the old 45-70 Billy Dixon...and have been really happy with it.
I Just now got in from shooting it... With 68gr 2ff Kik, compressed .285", a.030 gasket wad, and a 30:1 535gr.Postell seated to the last lube groove in a Rem case, 4 breaths. It just put 5 shots through the 300yrd target, off the bench, that measured 1 3/4"tall by 2 1/2" wide
.....But the load totally fell apart at 820yrds
..so i guess more shooting is in order.
The Sharps it the most fun you can have!
This is my 700yrd target...yeah only one hole...but the sight setting looks good! You can't really see the white Ram but it is at 887...and there is a few antelope just to the right of the Sharps forend on the knoll.