Point and Click Shooting - .58 Rifled Round Ball

[localfiend]

To make a long story short, I'm essentially getting a custom .58 rifle barrel for my Thompson Center Hawken. I want to shoot PRB as accurately as possible with powder charges towards the heavy end of the scale.

For the long story, look here:
http://www.muzzleloadingforum.com/fusionbb/showtopic.php?tid/285738/tp/1/


Ok, lets start with a short list of my goals.

1.) Accurate out to 100 yards
2.) Lethal enough to drop an elk at 100 yards
3.) Ease of use - Flatest Trajectory - Point & Click
4.) Manageable Recoil


Number 1 will deal directly with twist rate, which I'm hoping to figure out from input I get here.

Number 2 seems to be a bit ethereal. I've been doing a good bit of reading on PRB lethality, but it seems that not enough science has been applied to the subject to make a good measurement. Since that information doesn't seem to exist, I'm going to take a look at what data Is available and pehaps do some testing when I get my rifle back together.

To start with, I've been playing with the round ball ballistics calculator found here:
http://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/rbballistics.html

Through some internet searching I've come up with a set of velocities that seem to run from the low end, up to the medium-high end of the scale for a .58.

A bit of fiddling in excel and you get a chart that looks like this:

.570 Patched Round Ball
277.8 Grain
Sea Level Altitude
70 Degrees Fahrenheit



My first thoughts when looking at that data were; "Wow, round balls sure slow down fast!", and there must be hardly any felt recoil with those starting velocities.

I'm all for hearing input on what those velocities and energy reading mean, but I am aware that there isn't a lot of correlation currently. What we need are some tests with ballistics gel at varying velocities to see what happens. Then we might be able to make numbers mean something. Right now we've just got 100's of years of experience of PRB's killing things dead. :haha:


I believe I have solved Number 3 with the following two charts:

.570 Patched Round Ball
277.8 Grain
Sight Height from Bore Center 1"
Sea Level Altitude
70 Degrees Fahrenheit





Looks like more power is still better, not as much as it would be in a smokeless gun, but you can still flatten things out better without getting too crazy on the powder.

Also, I'm probably best off having a sighting point somewhere in-between 75 and 100 yards for the greatest consistency across that range.


As for number 4, I would like input from you all on what is reasonable.

From searching around on the board, and other places on the internet it seems that a powder charge of around 120 grains FFg is what it's going to take to achieve velocities above 1500 fps.

I'm pretty new to the world of muzzleloaders so that doesn't mean much to me recoil wise. If I compare that to my biggest smokeless gun. A .375 ruger, with which a standard load pushes a 300grn pill at 2660 FPS. This makes me think that the felt recoil of a heavy .58 is probably less than half as powerfull, perhaps a bit less than a .30-06.

If the recoil is actually around that level, I'm not going to have any problems at all on a shooter level. Flinching ect... will not come into play. The thing I don't know is what will that do the gun. I believe that Thompson Center may have manufactured 1" barrels in .58 cal, but I don't have any max load data. Anyone have any input on max loads?

I want to find the heaviest load that is reasonable, and then match the twist rate for best accuracy for that load.

 

[roundball]

I'll share some actual hands on info for what it's worth.

I used a .58cal 32" x 1:70" drop-in Flint barrel on one of my T/C Hawkens for a few years, it was the a proverbial tack driver for me with the following:
100grns Goex 2F
.62cal Oxyoke prelubed over powder wad
Oxyoke .018" pillow ticking
Hornady .570"

I was so impressed by what I called the .58cal's "Whompability" that when I had a long gun built for a big game rifle, I again went with the .58cal...this time a Rice 38" barrel with round bottom grooves and is also outstanding with the following:
110grns Goex 2F
.62cal Oxyoke prelubed over powder wad
.028" pillow ticking
Hornady .570"

I used a 50yd zero on both because 99% of my woods shots are 25-50yds through trees & branches so I wanted a laser in those conditions. Then I checked drop at 100yds and found it to be about 5" and planned to just hold top of the heart out around 100yd but have never had to. The .58cal will easily take deer, elk, moose, etc...a real powerhouse.

 

[Travis Gregory]

Somebody is seriously overcomplicating their shooting. A 58 will kill anything u shoot at and do it at any range that u are gonna be able to get a good sight picture with open sights. Just shoot your gun and get familiar with it. Find an accurate load and leave the charts and graphs for the centerfire sniper wanna bees. Enjoy the sport for its simplicity. :thumbsup:

 

[cynthialee]

I congradulate your math and what not but you are way over thinking this.
Get a black powder gun. Take it to the range, find your best load for your hunting ranges by shooting.
These guns do not react textbook always. Each gun has its' own quirks. Two guns of the same exact make and model may have as much as a 10 grain variation on what is best in that gun.
No amount of number crunching is going to tell you what is going to work best in your BP gun. It may get you in the neighborhood but it ain't exact.
So keep your numbers in mind as you shoot by all means but don't be afraid to adjust powder charge, patch thickness, powder type and so on....

 

[necchi]

I congradulate your math and what not but you are way over thinking this.

Yup! And the rest of what Cynthia said is spot on.

The 58 round ball will kill an Elk @ 100 if you can hit it in the chest with your most accurate load.
(there are members here that have done it with 50cals)
You've made a fine choice and at the right time of year. By the time you get things together you'll have plenty of range time before the hunt.

 

[Zonie]

I see your having fun with the numbers and your graphs show what most of us long time roundball shooters have known for a long time.

The thing that no chart or even ballistic gelatin can show is the killing power of a large diameter projectile.

Although they don't have the energy of a modern bullet, anything .50 caliber or larger is creating a wound that is as large or larger than a modern bullet will expand to. To add to this destruction, usually the soft lead projectiles we use expand to a larger size.

The amount of tissue damage is incredible and the shock from this damage can rapidly kill an animal.

There have been formulas postulated over the years to account for this and unlike the modern pound/feet energy formulas that add an unrealistic amount to their answers by squaring the velocity, these formulas include the size of the projectile.

For instance, K=WVD, where K= Killing power, W= projectile weight, V= velocity and D= caliber.

The answer is a pure number which only has validity when it is compared with another bullet,velocity, caliber number.

Take a .223 shooting a 55 grain bullet at 3100 fps.
Using the normal energy formula this round has a value of 1,173.86 pound/feet.
Using the K=WVD formula we have 55 X 3100 X .223 = 38021.5

Turning to a .535 caliber roundball at 236 grains at 1680 fps we have a energy value of 1479.32 pound feet.
Using the K=WVD formula we have 236 X 1680 X .535 = 212,116.8

Notice that the energy of the .54 is only slightly greater than the energy of the .223 but IMO, only a lunatic would expect to kill an elk with one shot from a .223.

Looking at the K=WVD answer, the killing power of the .54 is 5.58 times greater than the killing power of the .223

If you talk to the guys who do a lot of hunting with muzzleloaders, they will all say that the "Killing power" formula answers comes very close to describing what they have found in the field.

 

[galamb]

"Point and Click Shooting"

If you point, pull the trigger and hear "click", that's a bad thing - you want a "boom" :rotf:

As others have noted here, forget the charts.

From the Black powder Handbook (Lymans).

The difference in retained energy with a .570"/276 gr roundball over a few powder charges (Goex 2F) at 100 yards is:

80 grains = 532 ft pounds
100 grains = 594 ft pounds
120 grains = 643 ft pounds
140 grains = 712 ft pounds

The "experts" agree that you need 1200-1400 pounds of KE to kill an Elk (that's the muzzle energy with 100 grains).

Fortunately Elk are not "experts" :grin:

 

[localfiend]

Sheesh guys. This stuff is simple. Not at all like that nasty smokeless stuff. One powder choice, one bullet material, one bullet type... :grin:

Nothing I'm talking about here factors in all the little things you need to do to make your gun shoot the best - that's not the point.

The purpose here is to find the best starting point, because as simple as this is there is still a better starting option.

Shooting is math, and the best shooters research the base knowledge, keep it in the back of their mind, and figure out the best way to shoot without thinking.

In this case, higher powder charges give you a real world advantage. You can take inches out of the trajectory variation, and even at these short distances inches can matter.

There is a difference between the best load you can develop for your gun, and the best load the particular caliber is capable of. If you can find the best load the caliber is capable of, you can design your gun to be as close to that as possible.

Of course you still have to find the best load for your gun, but stacking as many variables as you have control of in your favor is the way to go. I plan to put several hundred rounds down range before hunting season this year, I just want the best starting point first.

Of course, this may all seem silly if you can keep your range around 50 yards. Unfortunately, up here in the northwest. 100 yards is generally considered point blank range. I've got to get used to the fact that even if I have a good sight picture, that bullet is hitting the ground. I regularly shoot smokeless out to 300 yards with irons, it's a huge change.

 

[Wes/Tex]

Totally agree with Cynthia and necchi. The ballistics charts are fine to fiddle with but the truth can be different. Honestly, the big rage was for the .54 over the .58 with the .54 side claiming it possible to get to the magical mark of 2,000 fps without going to real long barrels and real big charges. As far as basic facts go, they were right...you can usually get about 50 to 75 fps more velocity out of the .54 and about 50 fp more energy at 100 yards. Then, you have to consider the 40 grain difference in ball weight and the larger diameter of the .58. Roundball's comment about "whompability" is spot on! An elk, moose, deer , bear or raging Coors can will never know the difference!

If you're going with bigger charges, pick the slower rifling twist and deeper groove depth. Patched ball works better that way. Shoot it and have fun, besides there's no guararntee that a big charge is going to be accurate in your particular gun. Rifles have a way of upping the "humility training" level in this sport! :thumbsup:

 

[galamb]

Have you decided yet "who" is going to build your barrel?

They all have their own ideas of what may work best for what you are after and are more than willing to tell what they think will work.

 

[localfiend]

Have you decided yet "who" is going to build your barrel?

They all have their own ideas of what may work best for what you are after and are more than willing to tell what they think will work.

Bobby Hoyt is going to be doing the re-bore. He recommended a 1 in 60 twist as the most accurate in a Thompson Center length barrel for moderate PRB loads. Slower than that and the accuracy drops off unless you load heavy.

That discussion is what prompted this round of research. I wanted to determine what was considered a heavy load for a .58, and what advantages, if any, that would bring to the party.

 

[galamb]

Doc White built a couple of 58 round ball rifles and he recommended 200 grains of 2F for Elk.

Now I have quite a bit of respect for Doc, but don't think I would be dumping 200 grains down the barrel and pulling the trigger - at least more than once - figure it would take many months for the shoulder to heal :grin:

Even though the 58 hardly makes any "pressure" compared to say a 50, most barrel makers wouldn't recommend more than 120-140 grains (ok, a cover your butt thing on their part, but still lot's of power at those "max" loads).

If you could load 140 grains, shoot without "flinching" and keep it grouped well at 100 yards, go for it.

If not, shoot what you can. You won't be at any disadvantage shooting 100 grains instead of 140 - not really...

 

[necchi]

Dude, there are several other variables to consider in your quest for the beginning load. Ball size, patch thickness and your lube properties are just as important if not more so than your powder charge.
You have to determine your individual criteria within those variables together not as some random bunch of things that just work out when your goal is velocity and accuracy.

Go ahead, pick let's say 110grns of 2F as your charge,,
Now,, work the other variables for accuracy such as how thick your patch needs to be for the best group,, then work out how much lube is needed to make that group even smaller.

Then,,, start all over with a different ball size,,

you get it yet?

It's like someone on a CF loading forum asking what's the best load for my 308?
Well 42 grains of varget and a 168 smk will get ya close,, but now you need to fire form your brass, adjust neck tention and seating depth.

roundball gave ya two starting loads??

 

[azmntman]

I shot a conical with 120 gr once outta my .58. Wont be doing that again. :shocked2: OUCH

Posted before, My pop shot a buffalo at 50 yds with the .58 and a PRB and it whacked him hard, three leaps and down. 80 grains. Elk are not built any tougher. I'd rather hit a nice cow in the boiler room with my 75 gr load all day that put a 120 grain load just outside.

Get to the range and start the process. If 120 is the magic number then so be it but I can tell ya I have killed many many elk with 75 grains. They taste good as if ya overtenderized em with 120!

 

[coloradoclyde]

Necchi , Cinthialee, Wes/Tex, Turkhunter, and others are right you’re taking the fun out of it by getting to complicated. So I ask the question:
Does success =fun or does fun =success ?

 

[tecum-tha]

Holy manure! Just sight the thing in with it's most accurate load and kill an elk. .58 cal should like about 90 grains of 2F and you're good. Sight it in for about 75 yards, then you should rise your point of aim by about 2.5 inches @100 yards.
There are elk killed all the time with a longbow or recurve and you approach the simple killing of an animal like a big science project. I assume you only hunted with modern stuff until now.... How could the pioneers wipe out all those elk in KY without using spreadsheets, ballistic charts and chronographs???

 

[coloradoclyde]

Did you factor in”¦
Ӣ Altitude
Ӣ Humidity
Ӣ The Coriolis effect
Ӣ Gravitational variance
Ӣ Cosmic ray deflection
Ӣ Planetary alignment
Ӣ Moon phase
Ӣ And most important the amount of tension on the nut behind the trigger.

 

[Kapow]

I would consider starting out with a near max load and working backwards in powder charge weight to find an accurate load. Say, start at 130gn then work back to 100gn FFg. If you aren't getting the accuracy you need, change ball size/patch size until you do. That way you will develop a load that flattens your trajectory.

The lung area on an elk is pretty big so you should have a point blank rifle to 100yrds anyway.
Recoil is not that bad, I used to shoot 110gn Ffg with a 500gn Great Plains bullet, it was fine. I think a big .58 roundball is perfect hog medicine and have seen it penetrate end to end on solid boars.

I was re-reading some of Fadalas books the other night and he seemed almost obsessed with energy and velocity figures as a means of determining lethality. You can see why newcomers are sceptical about roundball killing power. It wasn't until I started reading this forum that the "death by diameter" thing made sense.

 

[necchi]

No clyde, it's not complicated to work up a load.
It is complicated trying to get your rifle shooting accurately when you use hypothetical numbers to run a ballistic spread and apply the formula to in field hunting.

 

[M. De Land]

My advice is don't over think or complicate the situation. Just get a good ,solid. uniform load that you can shoot well and go kill an elk.
I'd say 120 grains of 2F behind your patched ball will get the business done on any elk that ever lived if you can shoot and put the ball in the vitals at 100 yards. MD