Rifle shoots high?

[bryon knapp]

I have a .45 rifle I just picked up. It has 46inch barrel, 1-66 twist. I'm using .440 ball, .015 patch and 70 gr 3f. At 30 yards it was shooting point of aim, at 50 ish yards it shoots 6 inches high.... Is this normal? All sorts were taken from a rest.
http://rs713.pbsrc.com/albums/ww13...51011_115741009_TOP.jpg?w=480&h=480&fit=clip. 30 yards

http://rs713.pbsrc.com/albums/ww137/kingsax26/Junk/IMG_20151011_122043537.jpg?w=480&h=480&fit=clip. 50 ish yards

 

[kurts]

are your barrel lugs slotted to allow for the barrel to expand with the heat, that may be what is pulling your shots high.
good luck

 

[Semisane]

Is this normal?

No, it's not. With that load you should be getting something like 1750 fps. With a 30 yard zero one would expect it to be hitting about a half inch below point of aim at 50 yards.

Something goofy is going on. Most likely the sight picture you are using.

 

[smo]

Could it be that someone filed the front sight down too low? If it's dead on at 30 and high at 50 I would bet it's still higher at 75. If so you my need to install a new front sight and start over or if there's enough room try to take the rear sight down more that may help :hmm:

 

[longcruise]

Whether or not you are dead on at 30 yards is uncertain based on the target. Depends on what your exact POA was. If you were shooting at dead center of the bull (or cluster of bulls :haha: ), Then the center of your group is high at 30.

The trajectory of that caliber at the (supposed) velocity is still on the rise between 30 and 50.

How much higher It will impact at 50 yards will be dependent upon front sight height, sight radius and actual velocity.

Maybe you could spring for some "real" targets. :haha:

 

[jethro224]

First, no matter what you want to tell the girls, that ain't 6 inches. :haha:

2nd, yes that's normal.
A ball doesn't shoot in a straight line, it shoots in an arch.
At the muzzle you will be an inch or so low.
At a short range, usually between 12 and 25 yards, you will be dead on.
At medium range you will be a little high.
At longer range, usually 75 to100 yards, you will be dead on again.
At longer ranges you will be low, and lower, and lower...
It's just how the world works.

All of the above depends on your balls velocity and the height of your sights etc as was previously mentioned. Work up your most accurate load and adjust your sights to where the ball hits dead on at the range you want it to. Then shoot your rifle a lot at a lot of other ranges to figger out where it hits at different distances.

 

[Wes/Tex]

Is this normal?

No, it's not. With that load you should be getting something like 1750 fps. With a 30 yard zero one would expect it to be hitting about a half inch below point of aim at 50 yards.

Something goofy is going on. Most likely the sight picture you are using.

Agree...your question got me to looking and the difference between 25 yds and 50 yds should be on the order of 0,10" at your velocity. Granted there'd be a bit of wiggleroom but the difference shuldn't be that great for a .440" ball.

My first thought was that the ball was still climbing in it's arc and 50 might be higher than 25 but the difference should only be about 1/10th of an inch.

 

[don hepler]

I'm not a 45 cal. shooter, but 70grs. sounds like a lot of powder, to start with. I'd like to see the patch, coming out of that load. Like I say, I'm not used to shooting a 45 and that might be an acceptable load, but I'm wondering how accurate.

 

[Grenadier1758]

I took a look at the specifications of the rifle as posted in the Photos section of the forum. While you said you have peep sights, the sights are typical semi buckhorn iron sights. You have a 42" Getz barrel that is 1 in 66 twist and rifling is round bottomed. Based on that information you should not be seeing the impact rising 4 to 5 inches (based on a 9" paper plate if the POA is the center of the red dot on your paper plate. The charge of 70 grains of powder is a bit much, but with the 1 in 66 twist may require that much powder. You need to do a lot more shooting to determine the optimal accuracy powder charge.

Now it comes down to what is the sight picture? You want the top of the blade front sight to be even with the top of the notch in your rear sight. With the top of the front sight blade, the notch in the rear sight and the center of the target dot in alignment, the impact of the ball should be in a nearly touching group near the target point at 30 yards.

At this point we are just speculating on what can be done to resolve what is happening with regards to the trajectory of your ball. Tell us more about your sight picture.

 

[Dane]

Flintlock,

Not sure why we are getting such varied advice, and all the talk about sights, etc., but Jethro is right on.

Trajectory of a bullet is in an arc, that arc is based on a whole bunch of things,velocity, bullet weight, altitude, bullet ballistics, etc.

25yds.... Zero, 50yds, +?inches, 100yds, -?inches. It's simple physics.

 

[Semisane]

... 2nd, yes that's normal. ....

It just ain't so Jethro. :v

With that load it just not possible for the ball to hit zero at 30 yards and be on a rising trajectory beyond 30 yards. If it hits zero at 30 yards it will be below zero at all ranges beyond 30 yards.

Even if it hits a half-inch above the point of aim (i.e. the line of sight over the sights) at 30 yards, it will be only slightly above the line of sight - no more than a half-inch - out to about 50 yards, and will be below the line of sight beyond 50 yards.

With that load, if the gun was zeroed for 75 yards, it would be about 1.5" high at 30 yards and no more than 1.6" or 1.7" at any point between the muzzle and 75 yards. Of course, beyond 75 yards it would begin dropping below the line of sight.

 

[ZUG]

There is mass confusion in this post reguarding balistics, bullet path and line of sight.
First a bullet will always travel in a straight line when leaving the muzzle of a gun - gravity will always pull the bullet DOWN to earth - SO if you want to hit anything that is X diatance from the muzzle then you HAVE to rase your sights so that the bullets drop caused by gravity will hit the intended target at X distance -- please see figure below and BULLETS DON'T RISE when they leave the muzzle--- below is a quote from "Ballistics For Dummies"
"It doesn’t take a master’s degree in math or physics to understand a rifle bullet’s trajectory. The illustration below is exaggerated to show how the bullet, which is always falling away from the Line of Departure, intersects the Line of Sight at two distances, the second of which is the range at which the rifle is zeroed".

 

[longcruise]

Zacktly what I was trying to tell the OP.

for reference, here is his 30 yard target

and, here is his 50ish yard target

Looking at the 30 yard target, there is a wide range of possible POA on this target. If he held at the bottom of the mass of orange stickers, then the center of the three points of impact was well above the POA. This is going to put the ball on a trajectory to hit quite high at the 50 yard point.

Then, in addition, we don't know what was the exact poa on the 50 yard target. Do we even know the exact distances of either of the target?

Do we know the actual muzzle velocity or the height of the front sight above the centerline of the bore?

With all those unknowns, it is impossible to analyze the targets or the causes of any problems or to even determine if there is a problem!

Here is a rundown on the trajectory along with assumed parameters. Probably not an accurate depiction of what is going on but pretty accurate given the assumptions.

Name: .445 Cal, cast rb, 132 grn
Ballistic Coeff: 0.048
Bullet Weight: 132
Velocity: 1750
Target Distance: 125
Sight Height: 0.700
Temperature: 70
Altitude: 1500

Range Elevation Velocity
0 yds -0.70 in 1750 fps
25 yds 2.44 in 1438 fps
50 yds 4.51 in 1197 fps
75 yds 5.07 in 1041 fps
100 yds 3.68 in 946 fps

Without more precise info from the OP, it's pretty hard to draw any concrete conclusions. That was why I suggested better quality targets.

 

[Semisane]

That's exactly right Zug.

Now let's add a 30 yard zero to that illustration.



As you can see, there's no way a bullet hitting a spot on a target at 30 yards (i.e. zero @ 30 yards) can hit higher than the point of aim when aiming at any target beyond 30 yards. And there's no sight adjustment that would allow one to be dead on at 30 yards and shoot higher beyond 30 yards.

 

[jethro224]

Zug is exactly right and, sorry, but you are completely wrong.
First, scoot your 30 yard mark over to where the line of sight crosses the trajectory path, and then notice how much of the remaining trajectory path is ABOVE the line of sight.
If that doesn't convince you then go sight in your rifle dead on at 30 and then shoot it at 50.

 

[Zonie]

I just ran some numbers thru the ballistic round ball trajectory calculator on my computer.

When you guys are thinking about this question, don't forget, the line of sight is well above the bore because the top of the sights are above the bore.
This coupled with the ball rising above the line of sight can make the ball hit center at a close range like 30 yards. It may still be on the rise (relative to the line of sight) at 40 yards before it begins to fall back down to intersect the target at the distance the sights are adjusted for.

That said, the trajectory calculator says the rising or falling distance is a matter of just a few inches or less until a distance (range) of 70+ yards is reached. At these longer distances, the ball starts doing some serious falling.

For instance, a rifle sighted in for 100 yards, shooting a .440 roundball at 1700 fps muzzle velocity with the sights 1 inch above the bore is rising above the line of sight out to a distance of 60 yards.
The ball reaches the line of sight about 7 yards from the muzzle.
At 30 yards, it has climbed to 2.3 above the line of sight (LOS).

At 60 yards, it has climbed to 3.4 inches above the LOS.

At 90 yards, it has dropped back to 1.5 above the line of sight and at 100 yards, it hits at 0 for a bulls eye on the target.

Notice, no where are we talking about distances of 6 inches of climb or drop at the velocities 70 grains of powder will produce in a .45.

 

[Semisane]

.....First, scoot your 30 yard mark over to where the line of sight crosses the trajectory path

OK

If you can understand this.



You should be able to understand this. Remember, the ball begins dropping instantly upon exiting the bore.

 

[Zonie]

The chart you posted has an aim point distance of either 20 or 30 yards and a sight elevation of 1/2 inch (above the center of the bore). That's OK but it doesn't tell the whole story.

Move the sights up to .750 and move the aim point out to 80 yards and you will see the data says the ball climbs above the line of sight before dropping back to zero at the aim point distance.

 

[Semisane]

Well of course it does. It also climbs above the line of sight between the muzzle and 30 yards when the gun is sighted in for 30 yards.

In your example of using an aim point of 80 yards, the ball will be above the line of sight between the muzzle and 80 yards, but it cannot possible be above the line of sight once it passes the 80 yard mark. So it cannot hit "high" at 100 yards. Just as a ball that is hitting a target center at 30 yards cannot hit high at 50. (At least, not with the same sight picture.)

Quite simply, no matter the distance at which an iron sighted gun is sighted to zero, once the ball passes the zero point it is dropping - not rising.

You can get different results with a scope mounted high above the bore and high velocity rounds. In that case the round may cross the line of sight close to the bore, say 25 yards, and again out at 100 yards and beyond. In an iron sighted muzzle loader, the point at which the ball may rise above the line of sight is so close to the muzzle as to be meaningless - unless you're sighting in with something like a ten yard zero.

 

[coloradoclyde]

You should be able to understand this. Remember, the ball begins dropping instantly upon exiting the bore.

Theoretical....on paper only....
In the real world that is not quite the case.....
While gravity is a constant a sphere passing though air can exhibit lifting properties..
This is known as the Magnus Effect.