very slow twist

[coloradoclyde]

I'm also going to dispute the 1700 FPS velocity that Robins listed as a made up velocity for doing calculations and not an actual musket velocity....
To get a Musket ball going that fast would take something like 200 grains of powder..... :shocked2:

The accepted muzzle velocity for a Brown Bess service load is 1000fps......subsonic.

 

[George]

Here are some, but muzzle velocities alone won't tell you any of that. None of these balls "knuckled", obviously, or they wouldn't have hit where I aimed them. At least that's the theory, isn't it?

.30 = 2120
.40 = 2020
.54 = 1760
.62 = 1474

Spence

 

[George]

I'm also going to dispute the 1700 FPS velocity that Robins listed as a made up velocity for doing calculations and not an actual musket velocity....
To get a Musket ball going that fast would take something like 200 grains of powder..... :shocked2:

Well, my friend, if you won't accept what Benjamin Robins has to say, what chance have I?

I concede the field to an obvious expert. Live long and prosper.

Sayonara.

Spence

 

[M. De Land]

How do your good targets with rifles at 100yards compare to your good targets at the same range with a smooth bore.
I'm asking actual group size comparisons, say in five shot strings.
I'm curious as I don't have any smooth bores personally but have a cousin that swears they are just as accurate at 100 as is a rifle but I have never seen that this is true from friends that shoot them.
From what I have actually witnessed the rifle pretty much dominates past 50 yards.

 

[George]

I don't have records such as that to present, and they wouldn't be comparable if I did. I don't own a smoothbore with a rear sight, and I can certainly outshoot myself with a double-sighted rifle at distance. That isn't comparing rifled to smooth directly, though, just my sighting ability. My impression is based on a lot of years of shooting both, and the fact that I frequently surprise myself when shooting the smoothbore and getting rifle results.

Spence

 

[coloradoclyde]

None of these balls "knuckled",

You can't say that!...All you can say is that the affects were not visible on the target at the given range...

 

[coloradoclyde]

I'm also going to dispute the 1700 FPS velocity that Robins listed as a made up velocity for doing calculations and not an actual musket velocity....
To get a Musket ball going that fast would take something like 200 grains of powder..... :shocked2:

Well, my friend, if you won't accept what Benjamin Robins has to say, what chance have I?

I concede the field to an obvious expert. Live long and prosper.

Sayonara.

Spence

I'm not disputing Robins....I'm just saying that 1700fps isn't an applicable shooting velocity...
For testing purposes he may have been willing to sacrifice a rifle....the average shooter is not....That's all I'm saying

Your own .69 caliber doesn't even come that close.

 

[coloradoclyde]

Here are some, but muzzle velocities alone won't tell you any of that. None of these balls "knuckled", obviously, or they wouldn't have hit where I aimed them. At least that's the theory, isn't it?

.30 = 2120
.40 = 2020
.54 = 1760
.62 = 1474

Spence

Would I be safe to assume that smoothbores typically shoot more accurately at higher velocities?....

 

[M. De Land]

I would assume when ever the ball falls below 1300fps through about 950, fps same as a bullet.
I believe at least to this point in my learning curve that the pressure wave movement is a constant with velocity reduction and has little if anything to do directly with shape.
The correlation with shape is that the round or blunt nose has a very low Ballistic coefficient which sheds velocity quickly and is the prime mover of the pressure wave and turbulence which causes loss of stability.

 

[coloradoclyde]

My thinking is that the transonic transition moves the center of pressure far enough past the center of gravity to lever the ball into rotational movement....
Whether or not is has enough flight time left on the way to the target, is debatable...

The Magnus affect can clearly and visibly be seen if you watch a BB exit a Red Ryder BB gun....However in this case it is induced by the barrel...

 

[Artificer]

Your mention of smooth bore artillery and the subject of this thread got me to thinking of Flintlock Wall/Rampart Guns. They almost always were smoothbore, around 1 inch in caliber, used lead balls and were supposedly effective to between 400 and 600 yards. However, I have never read an explanation of what "effective" meant at those ranges. It may have been only as a "area" weapon rather than being able to hit a particular man at that distance.

Gus

 

[coloradoclyde]

Stranger still,....I use to fire tennis balls out of my cannon. Regardless of how much powder I used, they would go out about a 100 yards and they dive 90 degrees towards the dirt.....

Magnus affect?.... :idunno:

 

[coloradoclyde]

I have never read an explanation of what "effective" meant at those ranges.

Probably meant that when firing at a group of 10,000 men, somebody usually fell to the ground.... :haha:

 

[M. De Land]

I've watched smooth bore artillery shooting at targets on video several hundred yards away and once they got the range the repeatable accuracy was remarkable.
I would say from what I observed as a novice, that out to about 500 yards or so the smooth bore cannon was fully the equal of the rifled bore and projectile, perhaps a bit better by civil war standards which would have been far more practiced than the occasional shooting hobbyist of today.
I would further expect that the 500 yard limitation had more to do with the sighting equipment used than the bores inherent accuracy potential.

 

[Artificer]

At NSSA National Shoots and other places, I have witnessed some truly remarkable accuracy with 12 pound Bronze Napoleon Guns and Iron Balls.

I have read numerous accounts where those guns were accurate enough at 1,000 yards for counter battery fire, but that probably with explosive shot.

I imagine the Wall/Rampart guns on pintles, that I mentioned earlier, were used more like small artillery and were effective against formations, but not individual targets.

Gus

 

[excess650]

Something else to cogitate on: I've looked down the bores on numerous original guns. Some were rifled, some were smooth, and a few had STRAIGHT RIFLING. A couple that I have in mind were flintlocks, and presumably prior to percussion, so far earlier than Forsythe's slow twist/heavy powder charge experiments. Too, these had the attributes of a rifle, meaning patchbox/guard, cheekpiece, rear sight, and relatively thick walled oct/round barrels of .40-.50 caliber.

I've seen reference of pre-1750 Jaeger barrels with straight rifling as well.

I have to think these were intended to be loaded with PRBs.

 

[coloradoclyde]

STRAIGHT RIFLING

:shocked2: ..Pardon me a moment while I go throw everything out the window.... :haha:

 

[excess650]

I've been (mostly) following this thread, so pardon my modern observations:

I've shot RBs from a smoothbore double in shotcups and have developed some loads that are quite interesting. A load that shoots straight from my .725" bores all the way to 100 yards would sometimes knuckleball noticeably from a friends modified choke, but only after 75-80 yards.

I know that some modern shotgun barrels are cut with straight rifling to prevent rotation of the shotcup to enhance patterns.

It stands to reason that PRBs shot from straight rifled barrels would NOT rotate in the bore, and possibly very little in flight. The question begging to be answered is how accurate were these barrels? Possibly, the answer is not as accurate as a slow twist barrel(or else we would see a majority of straight grooves), but does anyone have documentation of comparisons?

Too, I wonder if any of the current barrel makers can cut straight grooves. :hmm:

 

[54ball]

Straight rifles do very well with shot and are better with ball than a smooth bore.

..Pardon me a moment while I go throw everything out the window....

Here's another one for you....square ball for use against Turks.

https://youtu.be/Mwhmk-4bDS4

 

[excess650]

The video is interesting, but the "accuracy" is poor. :haha: