Rifle shoots high?

[George]

Can't agree with that. It's an example of the flawed assumptions made about other things which happen to the ball inside the bore. Some people believe, for instance, that slower acceleration by FFg is better than the rapid acceleration of FFFg, but the only thing which matters is the velocity at the moment the ball leaves the muzzle, not what happened to it before that, not how it got there. Do it with compressed air, the trajectory will be the same. Your gun with the curved bore is like that, it has no effect on the ball after it leaves the muzzle.

Spence

 

[M. De Land]

It's before the ball leaves the barrel that the line of departure is established.
That is why a muzzle cut on an angle is reported to deflects the ball or bullet to the opposite side of the cant angle. It changes the departure angle just as if the barrel was bent that way.
Gravity has the same constant effect on the projectile but it's path in relation to that constant has been changed.
The reason sights have to be set way opposite from each other on a crooked barrel orientated horizontally is because the line of departure has been changed and the sights have to compensate to hit center.
When the same scenario is repeated with the barrel being orientated vertically the projectile will still be sent on a more angular path than if it were straight. The same angular path that was present when horizontal will now be doing the same on a vertical vector. It will result in a more looping trajectory patch than if it were shot on a straight line of departure.
This higher angle of departure is why the ball could conceivably be hitting higher at 50 yards with a 30 yard zero.

 

[George]

When the same scenario is repeated with the barrel being orientated vertically the projectile will still be sent on a more angular path than if it were straight. The same angular path that was present when horizontal will now be doing the same on a vertical vector. It will result in a more looping trajectory patch than if it were shot on a straight line of departure.
This higher angle of departure is why the ball could conceivably be hitting higher at 50 yards with a 30 yard zero.

No, doesn't compute. Remember that the gun is sighted in for 30 yards. That negates any effect you assign to the flight of the ball because it's being tossed higher than with a straight bore. Regardless how it got on that trajectory, it is now hitting on at 30 yards for both elevation and windage. Just as with a ball fired from a straight, properly centered bore, it can't shoot high at 50 if it shot on at 30.

Spence

 

[jethro224]

I have been convinced. If the rifle was TRULY zeroed at 30 yards it will not hit higher at 50.

 

[smo]

Anyone .....What would happen if you took too much off the front sight while filing and the rifle was dead on at 25 ? Where would the ball be at 50 yards low or high ? :idunno:

 

[M. De Land]

Good discussion Spence even though we disagree!
With the more looping trajectory angle from a higher angle of departure and given a 30 yard zero for both, what would change between the two is the second trajectory intersection with the line of sight.
Lets look at another example.
If a bullet is dropped from the same height as it is shot from a level line of departure it will fall back to earth at the same time as the shot one, the only difference is how far it traveled before it did.
Now take that same two projectiles and from the same height, point the one that will be shot, upward at an angle of 45 degrees ( greatly exaggerated for clarity) now they will not fall to earth at the same time because the angle of departure has been changed from level or in our case straight. The same thing can happen with a curved bore only on a much less dramatic scale.

 

[George]

The same thing can happen with a curved bore only on a much less dramatic scale.

We'll just have to agree to disagree on that one. It's just not right.

Spence

 

[Grumpa]

:bow:

But I'm standing behind what I wrote previously.

To quote from "Sighting-In The Black Powder Rifle" B.E. Spencer: "the bullet starts out below the line of sight, crosses it travelling upward, stays above it for a time, then begins to fall downward, crossing the line of sight exactly at the target....Once the bullet travels past the target, it will be below the line of sight until it stops, for whatever reason."

"The point at which that first crossing takes place is, on average, somewhere in the 10-15 yard range in front of the muzzle." (This assumes you want a 100 yard zero.)

Obviously, with a 30 yard zero, the projectile would never rise above the line of sight at 50 yards. The fact that this is exactly what happened (?) for the OP indicates that: a) his rifle was not sighted in for a 30 yard zero, or b) a whole bunch of variables that we have no access to - was he using a 6 o'clock or center of bull aiming point?... did he shoot from a solid, repeatable rest?...at 50 yards, could he see the bull using iron sights, well enough to be consistent?...this was an unfamiliar flintlock rifle, how comfortable was he shooting it?

Understand, I am NOT ragging on the OP (or anyone else), it's just that without more input from him we can't answer his questions, or resolve our "differences".

I have re-read this whole thread, and I think we are all arguing the same point, just seeing it from different perspectives. Until the OP shows up, we are wasting our efforts.

I am going back to the "Black Powder Notebook", and re-read the section on Practical Hunting Trajectories. I never realized that a dedicated squirrel hunter would zero his rifle in for 30 yards! I am continuously learning.

 

[jethro224]

I'm with you Grumpa.

And I also still say the OP's targets are "normal".

I think we are all arguing the same point, just seeing it from different perspectives.

:metoo:

 

[George]

Once the bullet travels past the target, it will be below the line of sight until it stops, for whatever reason."

Saying "When the bullet travels past the target..." is the same as saying "When the bullet travels past the sight-in distance..." In the OP's situation, it's the same as saying "When the bullet travels past 30 yards..." :grin:

Spence

 

[smo]

Anyone .....What would happen if you took too much off the front sight while filing and the rifle was dead on at 25 ? Where would the ball be at 50 yards low or high ? :idunno:

I vote for it will be higher ! :dead: :stir:

 

[M. De Land]

On my 45 cal target rifle I always have to crank in a bit of elevation when proceeding from the twenty-five yard line to the fifty. Same with the pistol.
Substantially more when we move to 100 and it gets unbelievable when we move out to 200 for the gong shoots. The round ball is coming down hill like a meteor as seen through the spotting scope.
If your bore is straight and the load unchanged you should be shooting a bit lower at 50 than at 25 yards if zeroed for 25.
The light conditions play a big part on elevation as well as windage on open sight guns.
An old adage for target shooters is " lights up sights up!

 

[Buckslayer]

Long time lurker, first time poster. Just have to get in my 2 cents worth

Assuming the sights are only .5 to 1" above center bore, I see no way for a 30 yard zero to hit high at 50 yds, assuming, again, that the sight picture is the same for both.

The only way I see the OP's issue happening is a change in the sight picture, or the line of sight being way above the bore. Using a weird example, let's say the sights are several inches above bore, yet zeroed for 30 yds. It might then be possibe for the projectile to be climbing at the 30 yd. mark,(near zero) and still climbing at 50.

 

[Grumpa]

But no one knows what the sight in distance was...it's all supposition.

Obviously, if he hit high at 50 yards after hitting around the bull at 30 yards - he wasn't zeroed for 30 yards.

 

[longcruise]

Welcome to your change of status from lurker to poster. Always nice to hear/read a new point of view. :thumbsup:

Any way, we have no idea where the rifle was zeroed. His POA might have been the bottom edge of the paper for all we know.

Just because his balls impacted in the neighborhood of his rather convoluted "bullseye" does not mean he was aiming there. If the actual zero of the rifle was 120 yards, the ball would have been approximately 2.75" high at 30 yards and about 4.25" high at 50.

 

[azmntman]

But what if we shoot dimpled balls? Golf balls fly weird?

2F or 3F? 4 Iron or 5 Iron? :idunno:

 

[Semisane]

That is why a muzzle cut on an angle is reported to deflects the ball or bullet to the opposite side of the cant angle. It changes the departure angle just as if the barrel was bent that way.

Sorry M.D., it just ain't so. The reason a muzzle cut on an angle deflects departure of the ball is because gas from the charge begins blowing past the ball on one side of the ball while the other side of the ball is still against the bore.

 

[M. De Land]

You didn't read the post correctly. I didn't explain the reason,(which I happen to agree with you about) for the angle cut crown causing the deflection only that it did so, the same way that it would if the barrel was bent that direction.
I was comparing the result not the reason for it's occurrence.

 

[Auldgoat]

Just a thought,,, could the OP have had a rather loose group that just happened to throw the shot high? Was this a consistent group? OR,,, how much powder did he REALLY use?

 

[Artificer]

You didn't read the post correctly. I didn't explain the reason,(which I happen to agree with you about) for the angle cut crown causing the deflection only that it did so, the same way that it would if the barrel was bent that direction.
I was comparing the result not the reason for it's occurrence.

Have to admit I thought the same thing Semisane did, until this explanation.

Sure, if a barrel is bent up, down, left or right; it will throw the ball in the direction the barrel is bent - when the muzzle is perpendicular to the bore.

If the bore is not parallel to the outer diameter or dimensions of the barrel, it will do the same thing. IOW, if the bore is rising in the barrel as it goes toward the muzzle, the ball will exit in that rising path compared to a bore that is parallel to the outer dimensions of the barrel. This is often referred to as "bore run out." Is that what you meant?

Gus