Round Ball Behaviour

[benvenuto]

someone should forward this thread to "mythbusters"... theres definitely an hour long TV show in here!

 

[weirdjack]

A clean barrel shoots low. A dirty barrel shoots high (more pressure applied to the ball per unit of time in the barrel).

No joking this time, I promise. I was thinking about this concept...
Keeping the charge the same, would not a dirty bore tend to slow the ball down....resulting in a lower point of impact (if your normal impact was with a clean bore). Remember, any pressure increase would be due to the "stuck ball" that is going slower than the same ball/charge in a clean bore. Slower ball would result in a lower point of impact....no?
It would be interesting to see some hard core bench-test results from various smoothbores.
But then I probably compensate for it by jerking upwards I use a .660 ball and .018 patch in a .689 bore. Thumb pressure seats the patched ball, no felt wad under it.
Jack

 

[roundball]

A clean barrel shoots low. A dirty barrel shoots high (more pressure applied to the ball per unit of time in the barrel).

No joking this time, I promise. I was thinking about this concept...
Keeping the charge the same, would not a dirty bore tend to slow the ball down....resulting in a lower point of impact (if your normal impact was with a clean bore). Remember, any pressure increase would be due to the "stuck ball" that is going slower than the same ball/charge in a clean bore. Slower ball would result in a lower point of impact....no?
It would be interesting to see some hard core bench-test results from various smoothbores.
But then I probably compensate for it by jerking upwards I use a .660 ball and .018 patch in a .689 bore. Thumb pressure seats the patched ball, no felt wad under it.
Jack

I've always understood that a slower projectile prints higher because it has more barrel time and the the muzzle is higher up in it's recoil arc at muzzle exit.

A faster projectile gets out of the barrel sooner while the muzzle is still lower down in it's recoil arc.

 

[weirdjack]

I've always understood that a slower projectile prints higher because it has more barrel time and the the muzzle is higher up in it's recoil arc at muzzle exit. A faster projectile gets out of the barrel sooner while the muzzle is still lower down in it's recoil arc.

Hmmmmmm.......Too much time spent shooting mortars.
True, the less time a projectile spends in the bore, the less likely the shooter can adversely affect it's flight. Some folks affect it with recoil muzzle lift, some drop the muzzle from flinching, some (like me) just wave it all around in the air and hope for the best!! So we could say that the ball could shoot higher, lower, left, or right...depending on the shooter. But.......
With all factors being as equal as possible (i.e. bench testing); I think physics will have the slower velocity projectile (round or pointy) spending more time in flight, allowing gravity to pull the ball closer to the Earth over an equal distance. It's why we aim differently when shooting uphill than we do shooting downhill, or why the ball hits lower at 50 yards than at 25 yards.
Now, it would be interesting to do some chrono tests to see how fouling affects velocity over a given number of shots in a smoothbore. Has anyone here done that recently? I wonder just how much slower the fouled ball would be travelling?
Jack

 

[taylorh]

A heavy bullet prints higher due to heavier recoil, not a faster bullet. The less resistance a bullet has within the barrel the sooner it will exit, and the more powder will go unburned out the barrel or burn outside the barrel as muzzelflash. An appropriatly tight fitting ball ensures that all your powder will burn before the ball exits the barrel. Now that you got me thinking, I'm going to have go and test these things to make sure that they are true.

 

[weirdjack]

A heavy bullet prints higher due to heavier recoil, not a faster bullet.

I give up!
Like someone said earlier....MythBusters would have a field day with some of these concepts!
Jack

 

[sherpadoug]

4 How high or low on the target the ball strikes is a function of how clean (friction free or tightness) the barrel is. A clean barrel shoots low. A dirty barrel shoots high (more pressure applied to the ball per unit of time in the barrel).
What do you guys think? :hmm:

From a conservation of energy point of view a clean barrel should give greater velocity and strike higher. The powder has a certain amount of energy to give. Any energy lost to friction with fouling is less energy for the ball. Less energy means less velocity, which means more time for the ball to drop before it hits the target.
:m2c:

 

[dlemaster]

A heavy bullet prints higher due to heavier recoil, not a faster bullet.

I give up!
Like someone said earlier....MythBusters would have a field day with some of these concepts!
Jack

Weird Jack
You may be on to something, giving this to Mythbusters. :crackup:
I have read concerning bullets in black powder cartridges that the heavy bullets print higher because of the arch in trajectory, lighter bullets print lower because they shoot flatter. All this is based on a single sight setting for both loads. ::

Regards, Dave

 

[roundball]

It's really not a muzzleloader issue.

6.5" barrled S&W N-Frame .45 Colt Ctg. Custom Hunter revolver.

Load it up with mid-range powder charges behind my 225grn JHP deer hunting bullet as weekend playing around loads, adjust sights for center bull, have fun, etc.

Load it up with the same cases, same bullet, but full power hunting charges, and it prints lower...less barrel time, muzzle exit is lower in the recoil arc.

 

[CoyoteJoe]

:agree: Like Roundball says, increased barrel time will place shots higher. That is most noticable with handguns because they recoil on a shorter radius but is a factor with all guns. Side by sides also recoil to left or right and barrel time influences that as well. If one matches a light bullet at high velocity against a heavy bullet at low velocity the difference can be extreme.

 

[taylorh]

:agree:

 

[Herb]

I do a lot of chronographing of rifled muzzleloaders I build, but have never shot a smoothbore. In rifles, the first shot out of a clean barrel is usually lower in velocity and strikes lower on the target than succeeding shots of the same load. A thin patched ball will give higher velocity than a thicker patched ball with the same powder and load. A larger diameter ball (in .40 caliber, say from .375 and .380 to .390 and .395) will give lower velocity than the smaller ones, same load. See some of my chronograph data in the Flintlock forum, 7/30/05 and 8/01/05.

 

[roundball]

In rifles, the first shot out of a clean barrel is usually lower in velocity and strikes lower on the target than succeeding shots of the same load.

This says that fouled barrels are faster than clean barrels?
:shocking:

 

[arcticap]

Barrel temperature may play a role as well. As the barrel temperature rises, the barrel expands and may cause trajectory rises. I've read that a barrel will stretch and vibrate as a bullet passes through the bore (harmonics). This can also be altered by barrel temperature which can impact the flight of the projectile. The degree of the barrel flex at the precise time the projectile exits the muzzle affects precision accuracy to some degree in most every barrel with the heaviest target barrels being affected the least. But those usually take longer to warm up and are then able to maintain a more constant temperature with less barrel flex, and better resulting precision accuracy as well.:hatsoff:

 

[Herb]

Yes, in my experience.