Barrel length and velocity of patched balls

[longcruise]

Here are some actual numbers that I chronoed with a TC Hawken 28" .45 barrel.


Shot on 05/30/10with TC .45, goex 3f, wally duck patch, spit lube

50grains
1517

70 grains
1680 +163

90 grains
1865+185

120 grains
2031 +166

I jumped from 90 to 120 because I was running out of that powder container. It's obvious that the returns in fps per grain of powder were diminishing but nevertheless velocity was increasing.

The scenario where high velocity can be of value above and beyond what is needed to kill is with trajectory. While the high velocity ball sheds velocity at a faster rate and the difference in velocity at say 150 yards has become considerably less than at the muzzle, the higher velocity in the beginning translates to less drop at the 150 point.

All useless if accuracy of the gun and skill of the shooter can't keep up.

 

[longcruise]

A seventy grain charge is plenty for much eastren deer hunting. It might be a bit light for mule deer or elk.

I concur with your entire post. I quoted the above to add to that. Ive killed two full grown mulie does with a 50 cal and 60 grains of powder. One at about 50 yards and one at about 80 yards. The 80 yard shot was from a 24" barrel. Both went down within sight.

We have a member here who I will not name to protect their privacy. He has killed elk. Many Many elk with a 50 cal rb and 60 grains of powder.

We tend to over estimate what is needed when the shot is placed correctly. The charge needed for rb and the general argument over rb vs conical is highly overblown on this site. It's always been a thing but has become more often argued as more hunters come over from the suppository side or the modern ml side. They are conditioned to think in a certain way and the only thing that will open eyes is hands on experience.

There are plenty of stories about animals lost and the round ball gets blamed. They all seem to be perfect shots in the vitals in the stories but of course no autopsy to clarify.

longcruise getting down off the soapbox now!

 

[oldschoolhunter55]

I may need to go get some popcorn for this one.

get me some too.dang im slow at all this stuff.

 

[Jay Templin]

generally, Longer barrels give the propellant force/pressure more time to work on propelling the bullet. i have heard all kinds of things in my life. one i have heard the most is a longer barrel has more time to burn the powder, this is no true. the explosion takes place, and the powder is burnt then and there., then the gas does its thing as it builds pressure, this is true with smokeless 100%, but black powder you will see embers come out the end of the barrel and small grains will still be burning, but that will affect velocity very little if any. i had one fellow tell me that when the bullet left the muzzle for about 30 yds it actually got faster! i told him no, it is like throwing a baseball, when it leaves your hand/muzzle, that was as fast as it would ever be, at that point it would only loose velocity. then i have heard this a couple of times, in fact the other day a friend of mine told me this. he said he had a magnum rifle of some sort, and it was so fast if you shot a deer with it at close range the projectile would go through so quick it had no time to expand! i told him it was like throwing an egg at a wall. i asked him, if you barley lob it at the wall or throw it with all your might what would do the most damage to the egg? he got it then. old tales die hard,,,,,,,,,,,,,,,

If I put enough powder behind it, do you think I could get a bullet moving fast enough to travel through time back to when the deer was standing where I was aiming? Asking for a friend…
Jay

 

[olskool]

If I put enough powder behind it, do you think I could get a bullet moving fast enough to travel through time back to when the deer was standing where I was aiming? Asking for a friend…
Jay

no, but if the barrel is long enough to get a foot from the deer you my hit him that away,,,,,,,,,,,,,,,,,

 

[Howard Pippin]

Not sure I totally agree with you. The ball is stationary in the breach. And the explosion excelerates it down the barrel, and it’s possible it will continue to excelerate for some more feet be it 5 or 20ft after it leaves a short barrel. But in a long barrel the bullet may start to slow due to friction before it’s only 3 ft up a 4 ft barrel , I am
Not trying to get into an arguments but thinking of applied maths from my college days 65 years ago. I’ll try to do some crono tests with my pcp air guns and write back. Mm yes an interesting subject on barrel length. I have a .45 old heavy barrel 24” long good bore but I ponder if it’s too short for BP and over 1600 ft / sec Recall BP has a max explosion of around 2100 ft sec I guess one could calculate the velocity at the breach explosion and velocity at end of barrel. But let’s face it it does not matter a hoot , barrel length is what suites you at the range of hunting.Mmmm for me never liked carbines , my latest ml
cape rifle has 32” barrels a big game ml 36”
Shortest 28” a Westley richards .5 double ml BP rifle but that would be for short range big game hunting

Just rambling along Nice to chat

Ps big game 577 rifle with 36” barrel





Nice to chat. N

I would appreciate it if you could add some kind of proof that something continues to accelerate after the acceleration force is removed. Everything I know of Might remain almost as fast as it did when it left the accelerant, but it definitely can't speed up without some force behind it.
Squint

 

[M. De Land]

I would appreciate it if you could add some kind of proof that something continues to accelerate after the acceleration force is removed. Everything I know of Might remain almost as fast as it did when it left the accelerant, but it definitely can't speed up without some force behind it.
Squint

I'm reminded of the false notion some hold that a bullet/patched ball rises after leaving a level barrel.

 

[M. De Land]

I used to wonder how fast my selfbows shot, I thought they were lightning fast, every arrow that I shot through a chronograph was a disappointment, just middle of the road in performance, so I quit doing it.

I like the black powder velocity calculator above, fun to play with but alas, my .54 with a 38" barrel shooting a .530 ball pushed by 85 gr of 2F (a super accurate load) is very middle of the road in velocity (subtract 100fps for goex instead of swiss) and according to the calculator is only burning 98% of the powder.

Both my selfbows and my flintlocks have caused a bunch of deer to take a dirt nap in short order, that is my main focus.

I still think that calculator is pretty neat so I bookmarked it for future use.

I'm currently finishing up a heat treated (charcoal baked) Hickory pyramid style flat bow for my grandson.
Never could figure any advantage a single shot muzzle loader had over a good self bow and quiver full of arrows at 30 yards or less!

 

[SDSmlf]

I would appreciate it if you could add some kind of proof that something continues to accelerate after the acceleration force is removed. Everything I know of Might remain almost as fast as it did when it left the accelerant, but it definitely can't speed up without some force behind it.
Squint

This fellow named Newton developed some laws years ago. His first law contradicts the notion that an object, such as a bullet, will continue to accelerate after the force accelerating it, say the force created from gunpowder in barrel, is removed and no longer working to accelerate the bullet. If we lived in an environment with no gravity or resistance from the air in atmosphere, that bullet would in theory continue on a straight line at a constant speed once it left the barrel, but it would still stop accelerating once it left the barrel. We don’t live in such an environment.

 

[Deavertex]

Not sure I totally agree with you. The ball is stationary in the breach. And the explosion excelerates it down the barrel, and it’s possible it will continue to excelerate for some more feet be it 5 or 20ft after it leaves a short barrel. But in a long barrel the bullet may start to slow due to friction before it’s only 3 ft up a 4 ft barrel , I am
Not trying to get into an arguments but thinking of applied maths from my college days 65 years ago. I’ll try to do some crono tests with my pcp air guns and write back. Mm yes an interesting subject on barrel length. I have a .45 old heavy barrel 24” long good bore but I ponder if it’s too short for BP and over 1600 ft / sec Recall BP has a max explosion of around 2100 ft sec I guess one could calculate the velocity at the breach explosion and velocity at end of barrel. But let’s face it it does not matter a hoot , barrel length is what suites you at the range of hunting.Mmmm for me never liked carbines , my latest ml
cape rifle has 32” barrels a big game ml 36”
Shortest 28” a Westley richards .5 double ml BP rifle but that would be for short range big game hunting

Just rambling along Nice to chat

Ps big game 577 rifle with 36” barrel





Nice to chat. N

Once the ball leaves the muzzle, the gas accelerating it will disperse in milliseconds. They may give a little push for an inch or two, but after that the ball is purely ballistic -- no more acceleration. You don't want a massive ball of flame every time you shoot, but a little bit is a good indicator that your barrel isn't too long. The shorter the barrel for a given load, the larger the fireball will probably be.

 

[Taevers]

I'm currently finishing up a heat treated (charcoal baked) Hickory pyramid style flat bow for my grandson.
Never could figure any advantage a single shot muzzle loader had over a good self bow and quiver full of arrows at 30 yards or less!

True dat

 

[Appowner]

Once the ball leaves the muzzle, the gas accelerating it will disperse in milliseconds. They may give a little push for an inch or two, but after that the ball is purely ballistic -- no more acceleration. You don't want a massive ball of flame every time you shoot, but a little bit is a good indicator that your barrel isn't too long. The shorter the barrel for a given load, the larger the fireball will probably be.

I'm not a rocket scientist but I suspect that's what we need here to properly explain it all.

 

[TCMonts]

And possibly to understand thè explanation!

 

[Gordoncourtney]

I'm reminded of the false notion some hold that a bullet/patched ball rises after leaving a level barrel.

Good morning bit if sun in London but damp and cold. On the subject of does the bullet excelerate after leaving the barrel, I had the notion it might absorb energy and thus keep excelerating for a few feet. Just don’t know. I put some shots over my crono with my 177 pcp bsa Scorpio, best I could do . Seems up to 10 ft from the crono in 12 inch at a time distances it neither speeds up or slows down . Here’s my figures 744 ft sec 2” from crono out to 10ft. 754. 750 . 755. 754. 752. 752 ft sec So seems the pellet just might slow down a bit , but as figures go totally inconclusive. Just a bit of fun for conversation.

I wish you well

 

[flconch53]

I'm currently finishing up a heat treated (charcoal baked) Hickory pyramid style flat bow for my grandson.
Never could figure any advantage a single shot muzzle loader had over a good self bow and quiver full of arrows at 30 yards or less!

You named the advantage when you said 30 yds or less. Nothing against self bows. I have a couple but once you cross the distance mark the advantage is apparent.

 

[M. De Land]

Good morning bit if sun in London but damp and cold. On the subject of does the bullet excelerate after leaving the barrel, I had the notion it might absorb energy and thus keep excelerating for a few feet. Just don’t know. I put some shots over my crono with my 177 pcp bsa Scorpio, best I could do . Seems up to 10 ft from the crono in 12 inch at a time distances it neither speeds up or slows down . Here’s my figures 744 ft sec 2” from crono out to 10ft. 754. 750 . 755. 754. 752. 752 ft sec So seems the pellet just might slow down a bit , but as figures go totally inconclusive. Just a bit of fun for conversation.

I wish you well

Years ago while in gun school we learned about expansion ratio which has to do with the ever increasing volume behind a bullet traversing the bore as the powder burns. This ratio is what determines pressure curves of various propellants and how they act upon a projectile while still inside the barrel. This ratio is what determines pressure, velocity and efficiency in a given barrel length.
Black powder burns very rapidly and seems to loose it's peak efficiency around the 30 inch length from what I can determine.
The other consideration is the weight of the projectile, how much of its surface engages the bore and how much resistance it produces while still in the bore.
Once the pressure behind a projectile begins to be over come by the counter balanced of resistance in front of it the velocity must decrease.
My guess is as the projectile begins to clear the muzzle and barrel friction resistance is replace by air resistance then there may very well be an initial increase in velocity. This is a moot point though as the only thing a chronograph measures is the projectile in flight long after it has left any reason for it to gain or loose velocity by the traverse resistance .
Now we inter the related but completely separate field of exterior ballistics which deals with the residual velocity, weight, shape, barometric pressure and rotation.
Interesting stuff this ballistic lot !

 

[doulos]

Just punched in some numbers on that calculator. It’s a bit slower than what I’ve chronographed for a 34 in 58 Colerain. The calculator stated I should get 1634 for 100 grains 2f Swiss. Checked my notes from a chrono session and I was getting a bit higher. Lowest was 1690. But most were in the 1700 to 1720 range.
Same gun 110 Goex 2f I was averaging about 1605 for just 5 shots.
Calculator is fairly close

 

[Gordoncourtney]

You named the advantage when you said 30 yds or less. Nothing against self bows. I have a couple but once you cross the distance mark the advantage is apparent.

The problem with UK it’s been illegal to hunt with a bow from around 1962. Mind you a bow is so quite nobody will know if discrete in hunting rabbits, a deer is another matter Seems bows and muzzle loaders are also banned from hunting in WA Oz as a frequent visitor, too old now for a 24 hour plane ride ,nothing much to hunt so what’s the point, barren land

They found Roos running around with arrows in them , hence the ban.

Took my compound to France but could not find hogs and not even robbers Those razor tipped arrows would frighten anyone, and so would my flint arrow heads

Good hunting

 

[Schaefer]

According to the simulator, Nope. At least not at 44”, or even out to 48” or beyond practical. Interesting to play around with the simulator, plug in your data in the link above.

View attachment 292028

 

[Schaefer]

According to the simulator, Nope. At least not at 44”, or even out to 48” or beyond practical. Interesting to play around with the simulator, plug in your data in the link above.

View attachment 292028

Simulators are great. But there is no replacement for a well thought out experiment and real data.