velocity comparison

[nathanbowenarrow]

Say you have a .54 prb(220gr.) and a .50 ball-et (220gr) both loaded with 90 br fff blackpowder all else being equal woul you get the same muzle velocity? or would one caliber burn powder more efficiantly to reach a higher fps?
:hmm:
Nathan

 

[Slamfire]

Probably not, you'd expect lower velocity from the .50 caliber, there's not as much area to push on, and the friction would likely be higher. :sorry:

 

[WV_Hillbilly]

:imo: Remember this is just my opinion, and you would have to do a real test to see which one is actually faster.

I would expect the .50 caliber projectile to have the higher velocity in this instance. :results:

My reason? Smaller diameter bore = higher pressure, which should produce higher velocity.

If I may, I'll refer a similar type of comparison from a reference to the Lyman Black Powder Handbook, though it is NOT exactly the same calibers, projectile and charge weights as your example--it is a relevant comparison.

.45 caliber, 28" barrel, 230gr Maxi, 60gr FFFg
1532 fps and 13,940 CUP

.54 caliber, 28" barrel, 220gr round ball, 60gr FFFg
1250 fps and 4,860 LUP

Please note that the pressure is measured in different units, but even at that, the velocity of the .45 is significantly higher. Also the .54 caliber projectile is 10gr lighter than the one in .45 caliber.

Smaller calibers "almost always" burn black powder more efficiently than larger calibers. :hmm:

Shoot Safely!
WV_Hillbilly :front:

 

[Tahquamenon]

The .50 cal will have higher velocity due to increased pressure in the smaller bore.

:m2c:

 

[nathanbowenarrow]

This is really interesting :winking:! So with this in mind why dont more guys choose the 50 loaded with a ball-et over the 54? would'nt the 50 cal ball-et cary more fpe out to a greater distance? due to the better coeficiency of the projectile? I do not have any experience with this only doing a little logical thinking... I think?

 

[nathanbowenarrow]

WV_Hillbilly,
Do you have an energy rating with those .45 & .54 loads? ::

 

[CoyoteJoe]

I think you have just discovered that conical bullets really are more efficient projectiles than roundballs, at least in terms of carrying more energy downrange. Of course, that don't mean the roundball isn't perfectly adequate, many centuries of use in hunting and warefare have shown it to be so.
Still, if looking to get the best ballistic performance in a hunting rifle you could do a lot worse than by trying to duplicate the old 45/90 blackpowder cartridge load. With a 300 grain bullet at about 1600 fps, it shot flat enough and hit hard enough to permit 200 yard shots and that is about the limit for iron sight hunting.
Lyman's Handbook shows a 285gr. Buffalo Bullet over 100gr. double F hits 1619fps from a 28" barrel and, if it's accurate, I'd consider that a fine elk rifle. Unfortunatly, Colorado has set .50 cal. as legal minimum for elk.
As the caliber increases, bullet weight must also increase if it is to retain ballistic effeciency. With increased weight one must increase the powder charge or settle for lower velocity and higher trajectory. Increased bullet weight and powder charge means greatly increased recoil. That can real quickly spiral out of reason, Which is why few old time hunters had use for a blackpowder cartridge larger than .45cal.
Round balls in calibers smaller than .62 can be loaded to good velocity without painful recoil. However, their downrange velocity loss limits them to about 100 yards, maybe 125 max and that is only on a windless day, from a rest, and with pretty sure idea that it really is 125 and not 150.

 

[Brittany1]

The ball-et and the round ball will have different ballistics coefficients - don't ask me what they would be, but they would be different. Different BC's are going to produce different velocities. Without doing math and all that, I would think the ball-et would produce a higher velocity.

 

[WV_Hillbilly]

WV_Hillbilly,
Do you have an energy rating with those .45 & .54 loads? ::

Yes sir, I sure do...

The .45 caliber 230gr Maxi at 1532 fps has 1199 ft.lbs.

The .54 caliber 220gr round ball at 1250 fps has 763 ft.lbs.

And of course the B.C. of that .45 caliber Maxi is probably about 2 1/2 times better than the .54 caliber round ball.
The .54 round ball B.C. is about .05 and the .45 Maxi B.C. is about 1.3

The notion is that if you're strictly using round ball, and you want more energy or "knockdown" power, you have to increase the bore size (which means a bigger, heavier round ball).

The smaller bore caliber can make up for it's diameter by using a conical which increases the bullet weight and the B.C., so you could possibly end up with a flatter trajectory, more velocity, more penetration, and more energy. That's a lot of factors to consider.

No matter what round ball gun or caliber, the round ball has some inherent ballistic characteristics and limitations that you just have to deal with.

Generally speaking, if a round ball starts out at the muzzle at 2000 fps, by the time it's at 100yds, it has lost about half of it's velocity (down to 1000 fps) and down to 1/4 of it's energy (as compared to the muzzle energy figure).

Doesn't matter what caliber round ball it is, though the larger diameter round balls do have slightly better B.C.s, it's not enough to cheer about. Conicals will always retain their velocity and energy figures better than round balls.

BUT... and this is IMPORTANT... a round ball may be MUCH more accurate than a conical in a particular gun, due to type of rifling, twist rate, etc... SO REMEMBER, extra energy won't help you if the bullet misses the target.

Shoot Safely!
WV_Hillbilly

 

[nathanbowenarrow]

isnt a ball-et designed to shoot out of prb barrels? My reason for asking about the 50 cal ball-et is to make the 50 more effeciant on elk out to 100-125 yards. :winking:
Nathan

 

[Rat]

Ok, don't forget that the .54, loaded up to the same pressure as the .45, or a .50, (which would take more powder) would have a higher muzzle velocity.

I believe a bigger bore, will shoot the same weight projectile as a smaller bore at higher velocity, with the same amount of breech pressure.

BUT, it takes more powder in the larger bore to do it.

Or in other words, the 60 grains of powder in the .54 is not producing the same amount of pressure as in a smaller bore. THAT is why the velocity is lower.

Be careful using the FPE formula to compare ballistics...it's a flawed formula. The Taylor KO formula is more realistic.

Remember a bigger bore has more frontal area, which does not figure into the FPE formula, but does make a difference in "real life".

Just some thoughts. Good discussion.

Rat

 

[Tahquamenon]

isnt a ball-et designed to shoot out of prb barrels? My reason for asking about the 50 cal ball-et is to make the 50 more effeciant on elk out to 100-125 yards. :winking:
Nathan

Nate,
Yes, shorter length projectiles will tend to stabilize better in slower twist rifling.

Not sure what rifling you are shooting (1:48, 1:66, etc).

The elk won't report you to the PC police if you shoot something else other than a roundball. I would not hunt elk with anything other than a 54+/roundball at close range or big concial with 45cal+ out to 100-150 yards.

If you are after elk with a .50, why not toss a hefty conical? Try these both with and without a wonderwad to find your best accuracy.

Hornady Great Plains (www.hornady.com) .50cal 385gr, 410gr or 460gr.
NoExcuses (http://members.aol.com/noexcusesb/index.html).50 Cal 460gr, 495gr.
Buffalo Bullet (http://www.thunder-ridge-muzzleloading.com/buffalo.htm) .50 CALIBER HOLLOW POINT
350gr, 385 or 410gr.

:m2c:

 

[nathanbowenarrow]

The barrel will be a 1 in 66 twist. I should have the rifle by augest-september. I will use it mostly for deer here in Texas (90%+) and feel it is more than enough for them out to 100-120 yards. Dont think a 54 would make much difference with whitetails. Was putting the question about the 50 ball-et out there because it will way aprox. 10gr more than the 54 prb and I should be able to push it to the same fps and thought that if the 54 prb kills-em dead out to 100 yards the same weight 50 ball-et should do the job out to the same distance. I plan to shoot prb for the whitetail and depinding on the results of the deer,Im sure thy will be great,It may give me the confidence to use the prb on elk. Just thought that I would get some opinions on the 50 ball-et because it should carry the same energy as the 54 prb, and the actual difference in the dia. is only .030 and I dont think this will make a noticable difference in energy no matter how you measure it ... momentium, Tayler value, Energy etc.. What do you guys think? :m2c: Nathan

 

[CoyoteJoe]

-- :agree:--All depends on accuracy in your rifle--shoot & see.

 

[Tahquamenon]

1:66/.50cal might have issues with stabilizing a longer projectile as in the heavier conicals.

There are also the REAL 320gr and T/C Maxi 350gr conical that I can get to shoot pretty good from 1:66.

If you are choosing caliber's, go with the 54 and shoot either a PRB, Ballette or a shorter conical. You might aslo try the minie bullet in .54 cal.

 

[nathanbowenarrow]

Im just thinking in the southern rifle Im getting that the 50 would be lighter and slimmer there for easier to carry and more pleasent to the eye. I have found weights for the swamped barrels and wish I could find weights for tapered! That woul help with stepping up to the .54. I dont want to go with a swamped .54 because of the 1.062 breech. I would consider a 38" 15/16 tapered to 13/16 (I was told would weigh 4.7lbs in 42" by some one in the forum) If I had the weight? What about a .54 15/16 tapered to 3/4 woul this be safe? would I have enough room for the front blade to be dovetailed in? You guys might be able to talk me in to the 54 (which I wanted to begin with) if you can help me find a way to keep the rifle thin and light. I really like the thin profile! Thanks Nathan :redthumb:

 

[roundball]

So with this in mind why dont more guys choose the 50 loaded with a ball-et over the 54?

IMHO, I think it's because folks who like the patched round ball, probably get round ball twist barrels with the thought in mind just to use actual traditional patched round balls...the ball-et is a modern design, really a small conical, not a round ball...so I think the desire to shoot traditional patched round balls drives the caliber selection regarding ball size/weight as it relates to the game and distances involved with their hunting.
:m2c:

 

[faw3]

Ya me too I get most anything to work in 1x66 up to 300 grs its something to do with bigger the bullet the better this will work and the speed, the guy that owns or did navy arms did a africa hunt all the 10 big game with a hawken 1x60 180 grs of fff and about a 600 grain minie ? what shoots out of my 50 mowrey works better out of 54. :front:

 

[Zonie]

Nathan: In responce to your question "What about a .54 15/16 tapered to 3/4 woul this be safe? would I have enough room for the front blade to be dovetailed in?" I'll say that I wouldn't do it.
Unlike a shotgun where the pressures are moderatly low, a .54 rifle is often loaded for maximum power.

When I made the Bastard Gun, which has a cut back Colerain swamped .54 caliber barrel, I was concerned because the "flair" at the muzzle was cut off. This resulted in a .860 octagon at the muzzle.

As I use a rather powerful 3D computer design system at work, I built a 3D model of the barrel (with rifleing) and then analyzed it for various pressures.
At 15,000 PSI internal pressure, the stresses weren't too bad, but when I cut a dovetail for a front sight into the model and reanalyzed it, the stresses became a concern.
The stress concentration around the dovetail was very high.
This analysis was assuming the barrel was made from a low carbon steel.

After this analysis, I decided to solder the front sight on rather than cut a dovetail for it.

The .750 muzzle you asked about is radially .055 thinner than my analysis and if you cut in a dovetail .060 deep it would be .110 thinner than my barrel. It would also have the stress risers caused by the sharp bottom corners of the dovetail.

If your barrel was made out of a high strength steel like 4130 or 4340 it wouldn't be much of an issue, but most muzzleloading barrels are not made out of those alloys.

 

[Rat]

Isn't muzzle pressure VERY VERY low?

What kind of loads develope 15,000psi in a .54? I always thought breech pressure ran around 8,000 to 10,000, although I know that some BP cartridge guns will go over 20,000 in some cases. But obviously I don't really know, digging into the dusty memory bin again!

Man that's interesting stuff that you can play around with that computer analysis and the muzzle loaders. Sounds like some good reasons to keep the rear sight pretty far forward. But again, doesn't breech pressure drop radically as the ball moves down the barrel?

Rat