Patched roundball for my muzzleloader

[Nightowl46]

Good evening...I am new to THR and by the looks of the info here, this is where I need to get the info that I need. I have been shooting a Parker Hale .58 cal with a lubed 500 gr. minie on 47 gr. of ffg Goex. I would like to know what would be the proper round ball size to use with this rifle. Thanks in advance for any information.

 

[Fingers McGee]

A .570 rb with a .010 or .015 patch would be my suggestion. I'd try both and see which combination the rifle likes best.

FM

 

[StrawHat]

I like to shoot PRB from most of my muzzle loaders but prefer a looser load than many think proper. I try to get the ball and patch to slide down the bore with little effort and still group well. Not as hard as it sounds, it just takes experimenting. I am not trying for one hole groups (but will take them if they arrive!) but merely good consistant hunting accuracy.

For your PH, try a 570 or smaller and patch up to fit.

Depending on the Model of PH you have, the rifling may be cut for optimum use with a bullet, not PRB.

 

[1911Tuner]

If the twist rate is geared to minie' bullets, the patched ball may not turn in top accuracy. Found that out the hard way with an old Navy Arms Zouave several years ago...after I'd popped for a RB mould. *sigh*

 

[mykeal]

To find the 'right' projectile for your rifle you need to determine the actual bore dimensions and twist rate. That information will get you to a starting place from which test firings of various combinations of projectiles, patches and lubes will show you what works best.

To find the twist rate, put a thick, lightly oiled cleaning patch on a cleaning jag and push it all the way down to the breech - you want a tight fit with the patch/jag so that it rotates with the rifling as it moves down the bore, so you may need two patches. Do not use dry patches, but you don't want them soaked either. With the jag at the bottom place a piece of tape around the rod at the muzzle, with the two ends of the tape pressed together to form a little flag that sticks out to the side. Slowly pull the rod out allowing the rifling to turn the rod. When the flag rotates to half a full revolution place another piece of tape on the rod at the muzzle. Remove the rod and measure the distance between the two pieces of tape. The rate of twist will be two times the distance in inches; if the flag made a half revolution in 24 inches the rate of twist is 1 in 48. A slow rate like 1:60 is best for round balls, and a fast rate like 1:20 is best for conicals. 1:48 is a good compromise for both, but you'll need to keep the loads a bit lighter for the round ball at that twist rate.

Determining the bore dimensions is more difficult. The best way to get accurate measurements is to slug the bore with Cerrosafe. That can be obtained from Brownell's and directions are included. If you don't feel comfortable using it, however, a vernier caliper can get you in the ballpark.

You want a ball that's about 0.010 smaller than the land to land measurement, although tighter would be better if the grooves are deep. Then choose a patch thickness that will, when doubled, take up the distance between the ball and the groove to groove measurement.

Finger's numbers are a good place to start if you don't have the equipment to make the measurement.

 

[[email protected]]

I have one, and the twist is 1-48. Mine shoots real nice with a .570 ball
.015 patch. And 50 grs Goex FFF. I replaced the musket nipple with a
no. 11 cap nipple. You can buy these from several sources. My old Navy Arms
"Zolie" Zouauve shoots 3 inch groups at 100 yards all day long with a .575
ball , .015 patch and 55 grs. Goex FFF. It has a 1-72 twist. Muskets are fun
to shoot. The thing that made the biggest difference in accuracy was the
nipple. I only use the "Ampco" musket cap to no. 11 cap. one. Have Fun!

 

[Nightowl46]

Thanks for the info...I really appreciate it.

 

[mykeal]

The thing that made the biggest difference in accuracy was the
nipple.

Why do you think that is?

 

[[email protected]]

The reason is the size of the flash hole. I used a musket nipple for a year in
compentition, and my shooting fell way off. Couldn't shoot like I had the year
brfore. Decided to shoot some 50 yd. bench with it and found out the groups
were in the order of 3 inches for 5 shots. I put the old nipple back in I had
used the year before with the little bitty hole and groups went back to the
normal 1 1/2 for 5 shots. I went back to winning again. No more musket
nipples for me. At least for compentition purpopses. It's been well proven
that any caplock rifle shoots more accurate with a nipple with a small hole
like the "Ampco" type nipples. Flintlocks are the same. When the touchole
gets much over .070 in dia. accuracy goes down the tube. Time to change.
In the big rifles at Friendship, some have to change nipples after only 5 shots.

 

[mykeal]

I don't dispute your claim regarding accuracy and small flash channels. I'm simply asking how 'accuracy', as measured by small groups (that is how you measure accuracy, is it not?) is affected by those small flash channels. What is the physics of the effect? How do small flash channels make the projectiles hit the target in smaller groups some 50 yards away?

 

[arcticap]

Perhaps the combination of #11 percussion caps and the Ampco nipple provided more favorable ignition for that particular load than the combination of musket cap and musket nipple could provide.
It would be more difficult to prove if it was only due to either the nipple or the primer than it is to assume that it was due to a combination of both.
However maybe the nipple did throw just the right amount of flash?

 

[mykeal]

I'm not asking for proof, just what he believes the physics are. I think it's an interesting idea, but I can't come up with a set of physical actions that make it work.

A small flash channel concentrates the hot gas from the cap ignition. It's a gas jet just like that from a rocket motor. The smaller column will be hotter at a given distance from the nozzle exit than one from a larger flash channel. Hotter gas certainly makes for more reliable ignition, but after traveling through the gun's flash channel it's got to be the same shape as gas from the larger flash channel. I don't see it having any ability to create an ignition that results in better accuracy. Reliability, yes, but a higher main charge gas pressure or faster rise time, no. And those are the only two parameters I can think of that might affect accuracy.

Musket caps produce about twice as much gas as standard caps, at almost 25% higher temperature. I can believe the concentrated gas jet from the standard cap on a Treso nipple makes up for that temperature difference at the main charge, but I don't see it being exceeded by any significant amount.

Just thinking about it, maybe too much. I'm going to go lay down now.

 

[arcticap]

I mention the primers because with all else being equal (well except for the human error factors when shooting), even different brands of 209 primers can create a noticeable accuracy difference with inline rifles.
Different types of primers (if not the brands) are also claimed to affect the accuracy of hand loaded cartridge rounds too.

 

[Acorn Mush]

What is the physics of the effect? How do small flash channels make the projectiles hit the target in smaller groups some 50 yards away?

Mykeal, I was thinking a larger flash hole would allow more gas pressure to impinge on the nipple as the powder burns. If the mainspring didn't hold the hammer real tight on the nipple, the hammer would be lifted off, resulting in pressure loss. It is possible the hammer may "unseat" to varying degrees for different shots resulting in either more or less pressure vented, which would affect accuracy. A smaller flash hole would maybe allow less pressure impingement and consequently less pressure venting.

Please understand I am not an engineer by any stretch of the imagination. I was just kicking the idea around in my head. Hope this came across in some coherent fashion.