OK
Bluegunner, you asked for it. So here goes.
First off, let me say I really like the gun and will never get rid of it. The Mustang is a well built rock solid gun with good fit and finish, but it's no target rifle. I love the top lever latch and sliding safety. It fits me well and it's just one of those guns that "looks right" to me. Its worst feature is its trigger. Mine had a lot of take-up with a long crunchy creep, but broke clean at the end. I had to work it over to get it to my satisfaction, but it's still heavier than what I would like.
My gun will shoot many load combination with acceptable hunting accuracy - around three inch groups at 100 yards - but I've not been able to get those famous "one hole groups". My best load will stay within an inch and a half or so at 100 yards. That load is a 300 grain Speer Gold Dot Hollow Point (#3974) over 120 grains of FFG Triple Seven (or 105 grains FFFG). That's my hunting load. I'm sighted in one inch high at 100 yards and it hits six inches low at 175 yards, which is the farthest I can shoot in my hunting area. I like heavy bullets for hunting.
I bought my Mustang in Feb. `07, and have shot close to a thousand rounds out of it. I like to experiment, and have shot .451 and .452 bullets in 250 and 300 grain weights in a number of different sabots, several jacketed and lead .458 bullets in MMP orange sabots, Lee REAL bullets, heavy Bullshop and No Excused conicals, Great Plains bullets in 385 and 410 grains, and probably a few others that I don't recall at the moment. I've shot loads with GOEX, Pyrodex, Triple Seven, and Jim Shockey's Gold powder. I would not hesitate to hunt with about 1/3 of the loads I've tried. I converted my ignition from 209s to .25 ACP, and find the ACPs cleaner. I also use Teflon tape on my breech plug, rather than grease. I've never had any difficulty removing the plug with the tape and it sure is cleaner than grease.
One thing I will caution you on. Be sure to clean and oil the internals of the action (trigger group, firing pin, etc.) after any extensive shooting. I use a spray can of carburetor cleaner from O'Rileys Auto Parts. Put the plastic tube in all of the nooks and crannies and blast away to get the crud out from any blow back. Then spray some oil in there.
Have you had enough yet??? If you want to do a little reading on some of my load experiments, here are some links to my posts on the HNI Black Powder forum. Most have target pictures in them.
http://www.huntingnet.com/forum/tm.aspx?m=2154935&mpage=1&key=Mustang�http://www.huntingnet.com/forum/tm.aspx?m=2849380&mpage=1&key=Mustang�http://www.huntingnet.com/forum/tm.aspx?m=2878971&mpage=1&key=Mustang�http://www.huntingnet.com/forum/tm.aspx?m=2692410&mpage=1&key=Mustang�http://www.huntingnet.com/forum/tm.aspx?m=2153706&mpage=1&key=Mustang�http://www.huntingnet.com/forum/tm.aspx?m=2531391&mpage=1&key=Mustang�