Short black powder rifle barrel?

[Catshooter]

I have just read on another board that most of the Holy Black burns in 18 to 20 inches and a barrel longer than that is just so much waste, as far a powder burning goes.

I have an old H&R Huntsman .58 with a 28 inch barrel. If I cut off eight inches would I lose velocity? I am just crazy? A 20 inch rifle is much handier in the woods, as most people know.

Weigh in please, I am quite new to the Holy Black and could use some input.

Thanks.


Cat

[1874Sharps]

Cat,

You will lose velocity by cutting back the barrel, but that may be an acceptable trade for ease of carry in the woods. One thing in your favor is the large caliber should make up for a little loss in velocity for common game. I am not so sure about most of a BP charge being burned nearly completely within the first 18 to 20 inches. Maybe that is true, maybe not, but shortening the barrel will reduce the amount of time and distance on which the gasses of combustion will act upon the projectile and therefore the velocity. As to the question of craziness, I can only say that everyone in the world is crazy except me (heeheehee).

[Bullshop]

You also loose sight radious. Not good for old eyes.

[Lead Fred]

Dont confuse modern ballistics with black powder ballistics. At 28 inches your already too short.

Using the Davenport formula, you will find that your FPS cap isnt much over 1600.
You shorten it, you might as well throw it at them.

[Catshooter]

Lead Fred,

Davenport formula?


Cat

[Lead Fred]

The following is a cut and paste from a tradional flintlock forum I belong to.
This formula has been around for years, and is used to determine the optimum burn amount of powder.
Please note I did not say most accurate. This only gets you close, and tells you when you war wasting powder.

I used 55gr for years, and a doulbe charge for longer shots. After doing this formula, I found the terminal volosity to be 2000fps, and 74.5grs.
So I was wasted a lot of powder. 55gr is still my accurate charge inside of 70 yards.


Take the bore diameter( or groove diameter and then calculate both cubic areas. Then subtract the area created by the lands, to get the actual true Cubic area of a rifled barrel. Generally, the difference is measured in a couple of grains, and is not worth the extra brain power used.) and divide it by 2 to get the Radius of the bore. (r)

Area of a circle is determined by the formula A= PiR Squared. Pi= 3.1416. So, Multiply the Radius by itself(to square it) and then multiply that number by Pi to find the area of the circle the diameter of the Bore of your gun.

Now Multiply that number( area) times the 11.5 to get the amount of powder in one inch of your bore. Multiply that number by the length of your barrel to get the total capacity for your whole barrel.


Example:


( .50 cal. divided by 2 = .25; times .25 = .0625; times 3.1416= .19635; times 11.5 =2.2580; times 28(barrel length)=63.22 grains of powder.)


If you want to know the cubic space inside one inch of a .50 caliber rifle, you can use .50 as the diameter, or measure the actual land to land dimension, and then the groove diameter, and then the groove depth, to work out EXACT the cubic area of that particular bore.


Here is how to calculate the Davenport Formula:


.50 divided by 2 = .25


.25 x .25 = .0625


.0625 times Pi( 3.1416)= 0.19635


.19635 x 11.5 = 2.2580


2.2580 x 28 inches( barrel length)= 63.22 grains of powder.


___________________

Assume you are shooting a 28 inch .50 caliber rifle barrel. The cubic area of that bore will be 28 x .19635 = 5.4978 cubic inches.

Now, because you do have grooves in that barrel, you can refine that a bit more.

Assume that the actual groove diameter of your gun is .501" ( my .50 caliber rifle's actual bore diameter)

Run the Davenport formula and you get:

.501 divided by 2 = .2505


.2505 x .2505 = .0627502


.0627502 x 3.1416 = 0.197136


0.197136 x 11.5 = 2.267064


2.267064 x 28 = 63.477792 grains of powder.

A cube of anything is determined by multiply the height times the width, times the depth, of the object. When you need to compute the cubic area of a cylinder, or other non-square object, it gets a bit more involved.

Now assume that the bore diameter is actually .490, and groove depth is .0055"( .501 minus .490 divided by 2 = .0055")( again, my gun's actual bore diameter)

Now assume that there are 6 lands and grooves, of equal width. The circumference of that bore( .490) is .769692" Divide that by 12( 6 grooves and 6 lands) and you get the width of the lands and grooves to be .064141".

To adjust the cubic area to correct for these "obstructions", you need to subtract from 5.519808 the area occupied by those 6 lands, that are .064141" wide, and .0055" deep.

So, multiply 6 time times .064141 times .0055 = .0003527"

5.519808 - .0003527 = 5.5194553 Cubic Inches


______________________________


If we ran the davenport formula using the Land to land diameter( bore diameter) of .490, we get:


.490 divided by 2 - ..245


.245 x .245 = .060025


.060025 x 3.1416 =.1885745 square inches. ( for a circle that is .490 in diameter.)


.1885745 x 11.5 = 2.1686067 grains per inch


2.168067 x 28 = 60.720987 grains of powder.


So, if you use the smaller diameter of the bore( land to land[.490]) The Davenport formula will give you only

60.72 grains of powder in that 28 inch barrel.

If you use the nominal .50 caliber, the formula gives you

63.22 grains of powder in that 28 inch barrel.


And, if you do all the math needed to actually get the ACTUAL cubic area of that barrel, you get a figure in between those two, 60.7, vs. 63.2! That is a difference of 2.5 grains, and half( assume that the lands and grooves are of equal width) that is only 1.25 grains!( Approx. 61.95 Grains!) Not enough to bother about, NO?

[waksupi]

Lt. James Forsyth said for a hunting rifle, that 26 inches was probably the most handy, and you could go down to 24" without loosing much advantage. If you go down to 18", I believe you could almost call it a pistol!
It would work, but not with a lot of velocity. I do know people who have shot deer and antelope with ML pistols.

[John Taylor]

Maybe this will help.
http://i95.photobucket.com/albums/l132/johnptaylor/blackpowdervelocity.jpg
I was always told that you needed 40" of barrel to burn all the powder, but then it depends on how much powder you are dumping down the barrel.

[Potsy]

If you're woods hunting, I suspect trajectory isn't a real big concern.
A .58RB weighs around 270 grains and most (safe) .44 Mag loads won't make 1300fps with that kind of weight.
Break out the hacksaw!!

[Catshooter]

Very informative & interesting gentlemen, thanks for the feedback. Good food for thought, that's for sure.


Cat

[Hellgate]

In my Lyman 2nd ed Black Powder Manual (Fadala) from the tables in the back (FFg Goex, .570 patched RB):
24" bbl: 60 grs powder=1188fps 32"bbl: 60grs= 1166fps
24"bbl: 110grspowder=1509fps 32"bbl:110grs=1543fps

The 460gr minie 575213-OS 24"bbl vs 32"bbl @ 60grs= 940 vs 965fps
" " " " " " @ 110grs=1278 vs 1334fps

Ballistics for a 28" bbl is going to be somewhere in the middle. as you can see there is not going to be a huge difference between 24 and 28" barrels. For brushy less than 50 yd shooting the short barrel is much handier to pack around in the woods (and around & inside a vehicle) than a 32' bbl. The 28 " is acceptable too. I've use both. The 32" is a bit too much for me to haul around.

In the shorter barrels FFFg may give a higher velocity compared to FFg. I've read that in smokeless powder shotgun loads that most of the velocity is achieved in the first 18-20" of the barrel but aiming is a problem with such a short sight radius.

see attached photo: 24"bbl 530gr minie 90grs fffg

[Potsy]

Don't know how much trouble it'd be, but if sight radius was a concern, he could just move back on the barrel and stick a peep sight on it. Be better off all the way around.

[Catshooter]

I'm pretty sure I'll be mounting a peep, I much prefer them.


Cat

[missionary5155]

Greetings
I hunted for years with my 32" barreled Zuoave .58 with 85 grains 2F. Only once did that barrel cause me any problem with a deer & I get a good laugh each time I rehearse the whole episode. My last 2 seasons hunting with that .58 I made my own peep sight. It is a joy to have installed and sped up accusition time easily 50%. I also have a 28" barreled .54 flinter and find it handier for being in a tree BUT I would rather have my 32" .58 walking about the woods. I do not feel a longer barrel is a hinderence once you learn how to carry it.
My 38" .50 flinter is lighter than the Zouave so it goes hunting more often these days. Then as soon as I get my 48" .60 smoothbore flinter restocked (probably next trip up here) it is going to be my hunter of choice. It never felt awkward walking through the woods and that long barrel makes fine sighting a snap. I think BALANCE in the rifle has more to it than a long barrel being "Woods Bad". If it balances just behind the forward hand giving it that "tad of muzzle heavy" balance I shoot much better. Part of the stalking procedure is to put yourself in a position where barral swing is not interfered with. That may not always be absolutely possible but it does figure in.
So me I would do a whole lot of thinking BEFORE I wacked a muzzleloader off. I have wacked off Winchesters, Marlins, shotguns & a S&W but NEVER a Muzzleloader.

[flinter62]

I had 58 cal. with 24" barrell. Loaded with RB & 60gr. 2F took couple deer with it,pleasure to carry.Wish i had it back. Do as you see fit. Flinter

[1874Sharps]

I was out yesterday shooting my 54 caliber Pedersoli 1859 Sharps carbine (22" barrel). The chamber takes a nitrated paper cartridge filled with a whopping 90 grains of FFFG behind a 525 grain ring-tailed boolit with the powder charge tied on to the ring-tail. It shoots great, although the sights could be a bit better. With that big powder charge and short barrel I am sure I am blowing some powder out the end of the barrel, but it still shoots accurately. Fortunately it can also be shot with a special brass cartridge that holds around 70 grains. Either way it shoots well and I would have no problem taking it big game hunting.

[Hanshi]

I don't care much for formulas except as intellectual exercise. I have a 24" .50 that's taken lots of deer with one shot. The remainder of mine are longer but it's not a consideration. While the longer the barrel the higher the velocity (as a general rule) a .58 prb "don't need no stinking velocity"!

[twotoescharlie]

lead fred. that's a long ,drawn out formula. but I guess it works, I have used it myself at times. while I was cacklelating it three nice bucks walked by me while I working on this formula.
I think I will just measure out my powder load and shoot like I usually do.

TTC

[357maximum]

some of my favorite toys have seen a hacksaw........do as you see fit, the deer will never feel the difference.

[Geraldo]

I don't care much for formulas except as intellectual exercise. I have a 24" .50 that's taken lots of deer with one shot. The remainder of mine are longer but it's not a consideration. While the longer the barrel the higher the velocity (as a general rule) a .58 prb "don't need no stinking velocity"!

Don't throw out the formula, just remember what it means. If you exceed the formulaic optimum charge you will still get increases in velocity, but they will be smaller for each given increase. So while the first ten grain increase in charge may give 100fps increase in velocity, a 30 grain increase in charge may only yield 180fps increase in velocity instead of the shooter's expected 300fps increase.

That said, I'm thinking of chopping a TC .54 barrel back to 20-22" just because I have one lying around that never gets used in its current configuration.

[Lead Fred]

lead fred. that's a long ,drawn out formula.


Thats why they invented calculators

Makes short order of it

[waksupi]

When I built my mountain rifle, I had originally intended going down to 24'. But, I cut it at 26" just to see how I liked it. At that length, it is very similar to a modern hunting rifle, and the proprtions of the rifle still looked good. I beleive if you go too short, it will look a bit odd.

[Catshooter]

waksupi,

Yea, when I cut a barrel I am pretty slow to get to the cutting part. Something about when it's gone, it's gone.


Cat