Group size @ 100 yards?

[Walks with Fire]

I am considering the purchase of a Green Mountain 15/16" .54 caliber 1/70 twist barrel for deer hunting. What size groups could I expect @ 100 yards considering no wind and benched shooting. Can I expect less than 3" groups with 100 grain charges or is this unrealistic? Overall what is the general opionion of the Green Mountain round ball barrels?

For those of you that have this barrel; What loads do you use?

[Ghost Bear]

Hi,
I have a flintlock of .50 cal with a 42" green mountain barrel in 1/66" twist.
Grouping looks like 1 1/8 " at 150 feet.
Didn't try it at 100 yd yet.
Charge is : 60gn Swiss Black Powder and .490 round balls. Patches are soaked with Leehigh Valley lube.

My uncle got a .45 with a GM barrel and his Ruger 10/22 got a GM barrel too ( one hole group at 150 feet ).
He is pleased with both of them.

You can go that way without beeing afraid.

[necchi]

I've got that barrel, took some shootin for break in (that's how I like to break in, others lap'm)

You gotta have good eyes and darn good control for better than 3" at 100 through iron sights, but I believe the barrel is a better shooter than most people.
A 100grns is a bit stout, I use a tight .020 denum patch, 535 ball over 80 grns and my bench group is 3-4",,off hand about the same,,my eyes are gettin older,,darn it!! I can make one hole at 75!

With my loading technique, that barrel like .535's, had ta go buy a mold. I tried a bunch of different lub/patch/charge combos with .530's,, just coulnd't get it sweet like it does with the 535

[Walks with Fire]

necchi;

Thanks; exactly the info I was looking for.

[Semisane]

I have a one-inch 1:70 twist 54 caliber Green Mountain barrel on my TC Renegade.

Last May I conducted a trajectory test shooting 85 grains weight of FFFg GOEX (95 grains volume in my TC U-View powder measure).  I shot 5-shot groups at 25, 50, 75 and 100 yards.  The targets are below.

I have a 4X Simmons ProDiamond scope on this barrel and certainly could not shoot as well with iron sights and my 65 year old bifocal eyes.  

Point of aim was the center of the round dot at all ranges and the scope was not adjusted during the 20-shot string.

25 Yards.


50 Yards.


75 Yards.


100 Yards.


Composite of all 20 shots.


NOTE: As you can see from the target notation, these groups were shot with .535 balls and a .016 thick patch.  That combination is fairly difficult to load and requires a hard SMACK on the short starter.  I recently changed to a .012 patch.  It not only loads a lot easier, but has reduced my 100 yard groups to right around two inches.

[blackpowderbill]

For a hunting rifle I am happy with anything that will shoot a three inch group at 100 yards.
My PH 1858 Naval Rifle will just hold three inches with a 596 gr bullet and 55 gr of FFF. I cant get any of my RB rifle to do that. They will shoot tight groups at 25 and 50 yards but start to fall off at 100.
 I can't shoot that tight in a hunting situation  so anything better would be lost on me. I won't intentionally make an unrested shot at a walking target at more than 50 yards.  In any event, the trajectory on my 1858 limits my shots to not much over 100 yards.

[Dillohide]

Have a 54 caliber Green Mountain barrel on one of my Renegades. I use 80 gr and it does 3 inches or better at 100 yrds but I don't usually measure the groups on my muzzle loaders. All I know is it will destroy the middle of a target in just a few shots. The 58 caliber Green Mountain on my other Renegade will do the same thing with a 90 gr charge.

[victorcharlie]

The groups out of my .50 caliber renegade 1/70 twist GM barrel follow semisane's almost to a tee.....my load is 70 grains of pyrodex.

Granted, my eyes aren't what they used to be.....