velocity comparison

[Zonie]

Rat: Yes, the pressures drop off rapidly as one measures them towards the muzzle. How rapidly? I have no information.
What are the breech pressure in a .54? Here again I have no real information, but I like you have heard of pressures in the 20,000+ PSI range with some blackpowder loads.

Putting all of this speculation together I chose 15,000 PSI as a possible maximum pressure, thinking that if someone put a 160 grain powder load under a 444 grain POWERBELT(tm) .54 caliber bullet the guess might not be too far off base. (I've read of folks who have what I call the BlackPowderMagnum syndrome who might think this is a neat load).
Anyway, when it comes to things that can blow my head off if I'm wrong, I choose to be on the safe side.

If it wasn't a lot of work, and if I wasn't up to my arse in snapping turtles I would build a model with a .75 barrel complete with dovetail sight, BUT, I really don't have the time.
Please don't take this personally, but if I did find the time, someone would ask the legitimate question you asked about the pressures I used in the analysis, and I couldn't defend them any better than I did here so, I'll just stick to my guns and say "I wouldn't build a .54 cal rifled gun with a .75 inch octagon barrel muzzle. Especially with a dovetailed front sight on it."

For the record, I did all my model building and analysis on my lunch break. :: :: :: :crackup: :crackup: :winking:

 

[OldHilljack]

Using that minie is real close to my TPHH (Trans Pasture Hog Homogenizer) rifle...It is a 62 cal English Sporting rifle, that shoots bullets, 1-40" twist and shoots a 900 grain .610 bullet over 120 grains of 2F...Chrono speed is in the low 1200 fps...Recoil is a bit stiff...calculated recoil is in the 100+ pounds, and I don't shoot a bunch of practice rounds...Shot a hog in the head at about 40 yards, and the results were UGLY....OHJ

 

[WV_Hillbilly]

Using that minie is real close to my TPHH (Trans Pasture Hog Homogenizer) rifle...It is a 62 cal English Sporting rifle, that shoots bullets, 1-40" twist and shoots a 900 grain .610 bullet over 120 grains of 2F...Chrono speed is in the low 1200 fps...Recoil is a bit stiff...calculated recoil is in the 100+ pounds, and I don't shoot a bunch of practice rounds...Shot a hog in the head at about 40 yards, and the results were UGLY....OHJ

:shocking: WOW! That's a pretty healthy bit of energy on both ends! From your load data and reverse calculation, your gun must weigh only about 8 1/2lbs (my math isn't so good anymore, so please correct me if I'm wrong).:hmm:

On which end of the rifle were the results UGLY? From that recoil number you noted, it sounds like the gun kills at the muzzle end, AND cripples on the breech end!

How many shots can you stand to shoot off the bench? I'd have a hard time with that gun off-hand!::

Due to an old shoulder energy, I am very limited as to the amount of recoil this poor old boy's body can take. I have to wear a PAST shooting pad whenever I shoot anything much over .45 caliber... and even at that some heavily loaded .45's are kinda iffy for shooting with my "bare shoulder". :cry: :boohoo:

Even with my limitations, I DO still like big heavy caliber guns. I think they are "fascinating" (as Mr. Spock puts it).

Shoot Safely!:front:
WV_Hillbilly

 

[faw3]

W V Hilllbilly can you pull up the ER for the 50 cal ? thank you. :front: :front:

 

[Rat]

No, yes, you are making perfect sense. If "normal" loads are in the 8,000 to 10,000psi range, taking it up to 15,000psi for analysis is not a big stretch at all. In fact, if a Sharps in .45-100 or .45-110 or .50-140 is getting in 20,000+psi territory, loading a rifle from the muzzle can't be that much different, pressure-wise, from putting it in a brass cartridge case. In fact, the cartridge case limits how much powder you can use, in the .54 you don't know what someone will pour down the barrel. So I'm with ya there.

However, and I may be wrong, but I still think muzzle pressures are very low.

::

Rat

 

[OldHilljack]

Well to be honest...I can only due about 5 shots and then it gets a bit touchy on the old shoulder, I don't try and shoot it hunched over it in the normal bench postion, tried that once and almost gave my self a black eye, I have made a rest where I can stand up and use it...Well the end result the hogs head looked like some one too a ice cream scoop and took about 1/2 of his head...The hog weighed about 150 lbs...Actually the rifle weighs is at about 9.5 lbs...The barrel was built by the Gun Works in Springfield, Oregon...And I built the rifle after a English Sporting Rifle...What a hoot to shoot...Does pretty well with RB too...

OHJ

 

[JoeC]

OHJ
If you like shooting your .62 , with that kind of recoil,
i have something you would really LOVE to shoot . It too is an English Sporting rifle (the only kind i would build when getting into this kind of recoil) ,
I have a 4-bore rifle that i built last fall. It has a
1.052 bore diameter , shoots a 1700 gr. 1.040" ball . Have shot it quite a few times with a 400 gr load of 2f . The last time out had a guy shoot it with 480 gr 2f . Made him
backpeddle quite a few steps.........(funny as heck) .
Joe.

 

[OldHilljack]

Well lets put it this way...I never said I liked it just that I did it!!!...I like shooting for fun and enjoyment ,not trying to see if I can keep the doctors rich...

I thought about building an 8 Bore but I over gun everything with my 62 Cal...I have built both ball (flint) and bullet (percussion)and that is about as far as I got "Thought"...Joe had a couple of nice barrels, he even had a "2 Bore" and I told him that it wouldn't be me on the end of that and besides I couldn't afford to shoot it let alone build it!!!

OHJ

 

[BS]

Using the same weight pojectile, the larger bore will have higher velostiy with less pressure. The same is true in modern guns, the 308 with 220 grain bullet will have a velostiy of 2300, 358 winchester[same case] can reach 2500 witha 220 grain bullet. Black powder is the same, diameter affects burn rate and expansion ratio. the lagre diameter bore will shoot a shorter bullet of the same weight, with less friction.....= more velostiy. Thats the way I see it! :m2c:

 

[OldHilljack]

Boy Mr.Chindemi your my HERO...Those Big Bores are really neat but the resulting facts are not for me...Simple Physics just kicks my rear...By the way what do you plan on shooting or hunting, besides anything you want...

If you would have any pictures I would be interested in looking at it...:thanks:

OHJ

 

[Howard]

All else being equal (like same twist, length of barrel, same percussion caps, etc.), I'd say that a .50 cal patched roundball pushed by 90 gr of FFFg will attain a higher muzzle velocity (perhaps as much as 200 ft/sec more) than a .54 cal patched roundball.

:m2c:

 

[CoyoteJoe]

:shake: Not so. You are forgetting that roundball sectional density increases with diameter. In other words, the ball is not only wider but also longer. The area on which the powder gas pushes increases with the square of the diameter but the weight increases with the volume of the sphere, diameter cubed.
That is why the roundball velocity champs are smallbores, you can exceed 2500fps in a .32 or .36 cal.
Not that it really matters, velocity in .50 cal and larger is mainly limited by manufacture's max loads or by how much recoil you are willing to suffer.
Powder does not produce velocity, but ENERGY. When folks speak of diminishing returns from increased powder charges they are usually looking at velocity numbers and wondering why it doesn't increase proportionally with the powder increase. If they looked at energy numbers they would find the proportions more nearly match.
That is not to say there is not a point of deminishing returns in energy, just that it isn't as radical as with velocity. :m2c: