Smoothbore vs. Rifle

[Joe Yanta]

Forgive me if this has been brought up before.

Given two exactly same firearms, both .62 caliber, same ingnition system, 36 inch barrels and both firing patched round ball of the same diameter with same powder charge. The only difference, one is a smooth bore, and one is a rifle bore.

Will they both have the same muzzle velocity?

The rifled bore will have an advantage of accuracy at a little further range.

In my experience the rifle bore accepts the patched ball a little easier.

Anyone ever experiment with this?

What is your take on this?

Joe

 

[musketman]

Given two exactly same firearms, both .62 caliber, same ingnition system, 36 inch barrels and both firing patched round ball of the same diameter with same powder charge. The only difference, one is a smooth bore, and one is a rifle bore.

"The rifled bore will have an advantage of accuracy at a little further range."
Out to a certain range (say 50 to 70 yards) the smoothbore can hold it's own against a rifle of the same caliber, the pattern will open up as expected with extended ranges...

"Will they both have the same muzzle velocity?"
I would think so, the powder charge and ball weight and barrel length being equal, this is where your velocity is factored in, if their is a difference it will be too miniscule to notice without specialized test equipment...

"In my experience the rifle bore accepts the patched ball a little easier."
If the barrel is coned I would have to agree, but the depth of the lands and grooves of any given rifle adds extra friction surfaces as compared to the zero depth smoothbore barrel...

(all answers are in my opinion, of course)

 

[Joe Yanta]

Thanks Musketman, I apprciate your thoughts on it.

My line of thinking was, pressure would be higher in the bore that had the greater resistance on the patched ball. Greater pressure would mean higher velocity of the ball at the instant the patched ball left the muzzle.

The patched ball in the least resistant barrel would leave muzzle slightly sooner but somewhat slower than the more resistant barrel.

I know that there are more important things in this world to be thinking about, but this is one of those stupid ponderances that pops into your head.

:yakyak: Carrying this ponderance further, if my thinking was even correct. You have one ball leaving sooner and one ball leaving faster, at what yardage would the faster ball catchup with the slower ball.

Working from 05:30 am to 11:30 pm your mind can do tricks on you. I should get some sleep and stop worrying about it. :hmm:

Joe

 

[nchawkeye]

OK....My opinion...The lead ball in the rifle barrel should/could/might "squat" or oblate more at ignition...Which should/could/might create a better seal of the gases...And should give the rifled ball a faster velocity....

This would be interesting to prove with a crony and assuming that the same amount of ramrod pressure is used on each to load...

 

In a modern rifle, approximately 1/3 of the energy from the burning powder is used to spin the bullet. No idea what the % would be in a round ball barrel, or if there is any difference at all but certainly some of the energy is expended to spin the bullet, so a rifle bullet velocity, all other things being equal, would be lower than that of a smoothbore.

 

[Stumpkiller]

Forgive me if this has been brought up before.

Given two exactly same firearms, both .62 caliber, same ingnition system, 36 inch barrels and both firing patched round ball of the same diameter with same powder charge. The only difference, one is a smooth bore, and one is a rifle bore.

Will they both have the same muzzle velocity?

The rifled bore will have an advantage of accuracy at a little further range.

In my experience the rifle bore accepts the patched ball a little easier.

Anyone ever experiment with this?

What is your take on this?

Joe

These are just my intuitive guesses.

Same muzzle velocity? No. Rifle will be higher (more resistance = more pressure = more velocity).

Accuracy advantage to rifle. Every time. (All else being equal). Some smooth rifles are more accurate than some rifles, but they're not equal and not in the same hands. (Tiger Woods is more accurate with a club and golf ball than some riflemen I have known over the same ranges :shake: ).

I found it VERY easy to load my Bess with a patched ball, also my New Englander. Just have to use a patch ball combo that is snug, not almighty tight. On the other hand, I can load a .530 ball with 0.010" patch with a single, easy push in my .54 rifle. Not the most accuate, but not bad. Good enough for gong targets on a woods walk.

 

It seems to me that more resistance would slow the bullet down, not speed it up. There is a law of physics, Venturi's Law, which states where the pressure is greatest, the velocity is least.

 

[tg]

Not so sure we are talking apples and apples here, as the load is increased in a given gun or a tighter patch combo is used the trajectory is flatter which indicates a higher velocity which is expected as the load/pressure increases, most charts show the relation ship betwen powder charge and velocity and energy, to compare a smoothboe and rifle guns of same cal. with the same load and an equally "tight" combo would have to be chronied to determine any difference in velocity. My .54 smoothbore when loaded with 70 gr 3f will drop faster than my .54 rifle with the same load the "tightness' and effect of the rifleing are wildcards that I cannot put a value on.

 

[Deadeye]

The smoothbore is GROOVE DIAMETER or BORE DIAMETER of rifle? If they are both bore diameter then the rifle will have the least resistance because of the deeper grooves and less velocity but it wouldn't be much.

 

[tg]

I think the law of physics that deals with higher pressure= lower velocity is dealing with hydraulics, not expanding gases moving a projectile.

 

[Gary]

Should we kick this over to the Bevel Brothers? :hmm:

 

[CoyoteJoe]

I can only say that when the military experiments in max velocity attempts they use a smoothbore to minimize resistance. With muzzleloaders I'd expect the difference to be negligible.