Excessive drop?

[Ezra]

Guys,

I have been testing different patches and have settled on a .015 cloth patch for my Chambers Lancaster in .58 caliber with a .570 ball.  I use 90 grains of GOEX 3f and bear fat lube.  I hit exactly at point of aim at 50 yards and 7" low at 100 yards relative to point of aim.  This is consistent.  It seems like excessive drop to me and was wondering what members thought.  The patch size is cut for .50-.59 caliber.  If 7" is too excessive a drop, the only thing I can think of is the patches are too small (diameter wise) and I am getting blow by.  Your thoughts?

Ez

[mjm46@bellsouth.net]

I use .020 in my .50 cal with a .490 ball. At 50 yards 65 gr 3f puts me right on at 100 yards 95 gr puts me on.

[Hungry Horse]

 Tighter patching might help some, but, if you wanted a flat shooter at a hundred yards, you should have chosen a .45,  or even a .40 cal. instead of a .58. You can make a .58 shoot flatter at 100 yards. but you aren't going to like the recoil.


                        Hungry Horse

[smylee grouch]

Do the recovered patches look burned?

[Ezra]

I have looked for patches post shot, no luck.  I don't mind my .58 having mortar like trajectories.  Just wondering if it was between the white lines.

Ez

[Standing Bear]

How high is front sight above center line of the bore?  Low sights aren't giving a big mid range trajectory. So if the ball is at high point at 50 it is immediately falling. If it continues to rise an inch or two after it passes the 50 yd target then falls the poi at 100 will be more like 2-4".
TC

[WaterFowl]

Here's some data from a 32" gm 58 cal. barrel..... this was shot in Feb of 2010

left column using leather wad with patch ..right column lubed fiber wad and patch
all shot with 3f Goex...

5 shot average for each load.
burned lots of powder that day.

.....Leather wad..........500 fiber wad
80 gr.....1447...............1286
85 gr.....1561...............1400
90 gr.....1638...............1541
95 gr.....1679...............1499
100 gr....1584...............1539
105 gr....1561...............1629
110 gr....1548...............1679
115 gr....1628...............1655
120 gr....1731...............1726

I have better accuracy with some type of wad under the patch in my bigger bores.
In checking my note book  105 fff goex and 100 ff Goex were good shooters.
side note..I sight in zero at 75 yards..that way the rb still hits in the vitals at 100 yards.
Now to get a deer to stand still..HaHa.

[Dphariss]

Guys,

I have been testing different patches and have settled on a .015 cloth patch for my Chambers Lancaster in .58 caliber with a .570 ball.  I use 90 grains of GOEX 3f and bear fat lube.  I hit exactly at point of aim at 50 yards and 7" low at 100 yards relative to point of aim.  This is consistent.  It seems like excessive drop to me and was wondering what members thought.  The patch size is cut for .50-.59 caliber.  If 7" is too excessive a drop, the only thing I can think of is the patches are too small (diameter wise) and I am getting blow by.  Your thoughts?

Ez

The ball needs to be about 2.5" high or a little more at 50 to give decent trajectory.
Sighting a hunting rifle for 50 yards is a mistake.
Hunting rifles for deer/elk need to have the zero as far as possible to keep the mid-range within 3" or a little less of line of sight.
For a 58 RB at 1650 this will mean 110 yard zero depending on whose ballistics calculator is relied on. The Hornandy site with a guessed .072 BC sighting at 110 will keep the ball at 3" or less of line of sight to 130 yards or so.
If 1750 is used then the same zero will put the ball closer to line of sight all the way to 130.
Sighting at 50 puts the ball about 4.5" low at 100 and almost 10" low at 125.
With 110 zero no hold over is required to 125-130 yards. With the other a center of shoulder hold at 125 may blow off a leg.

Dan

[smylee grouch]

Ezra: Switch to 2f and see what happens. I have shot 58s forever and use 2f and have not had excesive drop on any of the several 58s that I have owned and shot. !00 gr. 2f Swiss is my best load for my present 58.

[Ezra]

Thanks for all the replies guys.  Smylee, I will try your load in 2f when I get a chance.  I appreciate it. 

Ez

[Daryl]

Since retrieving my .69, I relegated the SXS .58 Kodiak that I'd obtained for hunting moose, to trail walk and target shooting.  It shoots groups that centre an inch apart at 100 yards alternating barrels with either 100 to 110gr. of 2F GOEX.  It's a hoot to right, then left a gong while the sound is still ringing.  

I zero'd the rifle zero'd at 50 yards and for 100yards, the bead's diameter above the notch held in the target's centre will give a centre hit with my most used load, 100gr. 2F. I do not know the velocity as the steel targets merely ring when hit and this rifle rarely missed last year, no matte the range.
 
I got tied of casting  SC .573"/.574" (.570" Lyman mould) round balls so I sold it at the recent gun show. It's best patch with that ball or the .564" Lee casting, was a mic. ratcheted .023".

I agree with Dan, in that for a hunting rifle, sight it to zero it to give you the longest point blank range. 3" above of below the line of sight will do it for deer, moose, elk and bear, although most black and grizzly bears are shot at 50yards of closer and during the rut, elk and moose can be coaxed (called) in to bow range.

I find .015" patches too thin even for cleaning patches.

[Standing Bear]

5-29-13

TCompton,

Please explain how "Low sights aren't giving a big mid range trajectory".

Best Regards,

Robert

Higher sights don't guarantee less drop but they can be a solution.

All projectiles must rise above the center line of the bore to cross the line of sight.  The projectile then reaches it's apex and begins to drop, crossing the line of sight again at a further distance.  These to points are further apart on modern high velocity rounds with lower drag and therefore less drop over distance.

The ball can be rising at 50 yards when crossing the line of sight and may get an inch or more above line of sight past the 50 yard target.  It starts dropping further out and therefore has less net drop at 100.

It is possible to have the projectile cross the line of sight before the 50 yard target and be dropping at 50 yards and have a greater net drop at 100. 

With a lower sight the ball rises very little if any past the 50 yard sight in and starts to drop sooner resulting in a greater net drop.

I use high sights, sight in with the max accurate load at 100 then check the mid range POI.  If that is acceptable, el fin. 
TC

[Ezra]

5-29-13

TCompton,

Please explain how "Low sights aren't giving a big mid range trajectory".

Best Regards,

Robert

Higher sights don't guarantee less drop but they can be a solution.

All projectiles must rise above the center line of the bore to cross the line of sight.  The projectile then reaches it's apex and begins to drop, crossing the line of sight again at a further distance.  These to points are further apart on modern high velocity rounds with lower drag and therefore less drop over distance.

The ball can be rising at 50 yards when crossing the line of sight and may get an inch or more above line of sight past the 50 yard target.  It starts dropping further out and therefore has less net drop at 100.

It is possible to have the projectile cross the line of sight before the 50 yard target and be dropping at 50 yards and have a greater net drop at 100. 

With a lower sight the ball rises very little if any past the 50 yard sight in and starts to drop sooner resulting in a greater net drop.

I use high sights, sight in with the max accurate load at 100 then check the mid range POI.  If that is acceptable, el fin. 
TC

TC,

That is a very excellent explanation.  Even I understood it.  Thank you for that.

Ez

[Standing Bear]

Thank you and you are welcome.
Tc

[Daryl]

Sight heights are relative. Thus, a set of sights that are 1/8" inch above the barrel flats are low sights in comparison to a set of sights that are 1/2" or 5/8" above the barrel flats.

The lower the sights, the easier the closer range shots are, as in string cuts or horizontal straws.  The ball needs a longer distance (further from the muzzle) to rise to the level of the sights if the sights are higher off the barrel. For strictly hunting and not having to stop bear or tiger charges at close ranges where pin-point brain punching accuracy is necessary, higher sights can be of benefit for a hunting rifle. If higher sights cause a low hit on a charging bear, that is not a good thing. (ball has not travelled enough distance to come up to the sights - yet) Much depends on the size of the bear, of course.

 

[Dphariss]

6-1-13

TCompton,

Thanks for the reply.

Please provide an example of "High sights" and "lower sight" as you have discussed in your reply. What constitutes the difference between "High sights" and "lower sight"? Is there a specific dimension that makes the difference? Are you talking about both the front and rear sights in your explanation?
I am trying to grasp your explanation and understand why "High sights", "can be the solution" to excessive drop.

Best Regards,

Robert

They are not a solution.
If carried to an extreme as in some modern firearms they can result in the bullet striking too low to be useful at close range. The high sights can be an advantage in a military rifle where the targets are often tall.
 
Excessive drop, in our context has two causes, the rifle is zeroed at too close a range, like 50 yards, or the velocity is too low. Either can cause the ball to be too low to be really useful at 100 yards. Most round ball rifles loaded to 1700 fps or more produce the lowest trajectory when 2.5" or a little higher at 50 yards this will produce a 110-130 yard "point blank" range for deer sized animals. Small game rifles are best zeroed at 40-50 yards since squirrels are seldom shot at 100 yards with a ML.
Higher sights can allow the rifle to be zeroed at close range 15-25 yards and the built in rise generated by the higher sights will then put it "on" again at perhaps 100 yards +- (for BP arms) or even 300 in the case of the AR-15 platform.
With MLs the advantage of the slightly higher sights is that they are less effected by mirage off the barrel.
For our purposes a front sight more than about 1" over the bore centerline is usually not needed.
Dan

[Standing Bear]

I use 1/2" high sights (front and rear are nominally the same but front will get filed some) which puts center line of bore about 1" below the top of the sight with a 1" barrel.  Sighted in at 100 yards the ball will never be more than 1" low and that AT the muzzle.

I don't use the high sights so much for the trajectory affect but because I find the sights easier to see and in hot weather (I am in central Texas) heat waves from the barrel are less of a problem if not eliminated all together.
TC

[wmrike]

That pretty much duplicates the path of my .54 w/70 grs.  It rises thru the line of sight at 50 ft., passes back thru line of sight at 50 yds., and impacts about 7" low at 100 yds.

I played around with a ballistics program, co-efficients, height of line of sight, caliber, all that stuff, and backed out a muzzle velocity of about 1500 fps that answered all the observed conditions.  Fun stuff.

I suppose I could boost the charge to get a flatter trajectory, but within the 30-70 yd. ranges that I typically shoot, the 70 gr. charge is the most accurate.

[P.W.Berkuta]

Tighter patching might help some, but, if you wanted a flat shooter at a hundred yards, you should have chosen a .45,  or even a .40 cal. instead of a .58. You can make a .58 shoot flatter at 100 yards. but you aren't going to like the recoil.


                        Hungry Horse

You hit the "Nail on the Head" +1

[Ezra]

Tighter patching might help some, but, if you wanted a flat shooter at a hundred yards, you should have chosen a .45,  or even a .40 cal. instead of a .58. You can make a .58 shoot flatter at 100 yards. but you aren't going to like the recoil.


                        Hungry Horse

You hit the "Nail on the Head" +1

Like a stated previously, I am just fine with the mortar like trajectory.  Just was wondering what folks thought regarding whether or not it was consistent with what they have experienced.  If very much prefer a fat, slow punkin' to a small faster one.  Sort of fits with my personna...

Ez

[Long John]

The degree of drop at any distance is primarily a function of bullet velocity.  If you want less drop at a given distance you have 2 choices:  speed up the bullet or compensate for the descent of the ball with a higher rear sight.  Most of us have to select a compromise as we use our rifles primarily for hunting and target shoot primarily to stay in shape.

My 54 rifle shoots a .520 ball with .024 denim patching over 85 gr of FFFg GOEX powder.   This gives me 1720 FPS muzzle velocity.   I sight it in for "on" at 75 yards so it is about 1.0 inches high at 50 yards and 2.5 inches low at 100 yards.  It is also "on" at 25 yards as the ball is still rising.

Each rifle has to be tuned by adjusting the load to find the best compromise between accuracy and tragectory.  I could get flatter tragectory by loading my rifle "hotter" (more powder) but my accuracy suffers and so does my shoulder.

Best Regards,

John Cholin

[Ezra]

Yeah, I still have work to do.

Ez

[Standing Bear]

It doesn't start to drop upon leaving the barrel when the bore is pointed up. I'd does start to slow. Drop then begins when the projectile passes the apex of the arc.

TC

[Don Getz]

Maybe someone should write a book on this, or, maybe it has already been done.....several times.   Maybe we should back up
to Ezra's first question.     He states that it shoot to point of aim at 50 yards, and shoots well at 100, but is 7" low.  What is
wrong with that?  No matter what we do, a 58 cal. rifle will not shoot flat out to a 100 yards.   You can change his sights to
hit at point of aim at 100.......would it not shoot 7" high at 50?   He already stated that the gun shot well, why would you want
to change patches?   He might want to try a heavier load, it might change the amount of drop he is now getting at 100 yards,
but, will it still group well?   He will get a lot more shots at a deer within that 50 yard range than he will at 100.   I was amuzed
by the one solution that he needs higher sights, not really sure what that would do...............Don

[Dogshirt]

Maybe someone should write a book on this, or, maybe it has already been done.....several times.   Maybe we should back up
to Ezra's first question.     He states that it shoot to point of aim at 50 yards, and shoots well at 100, but is 7" low.  What is
wrong with that?  No matter what we do, a 58 cal. rifle will not shoot flat out to a 100 yards.   You can change his sights to
hit at point of aim at 100.......would it not shoot 7" high at 50?   He already stated that the gun shot well, why would you want
to change patches?   He might want to try a heavier load, it might change the amount of drop he is now getting at 100 yards,
but, will it still group well?   He will get a lot more shots at a deer within that 50 yard range than he will at 100.   I was amuzed
by the one solution that he needs higher sights, not really sure what that would do...............Don

In some parts of the country you might get more shots at deer within 50 yards. But here in eastern Washington
where Ezra and I live that is not the case. Wide open, with just sagebrush and bunch grass for cover. If you can get
within 100 yards you are lucky or have exceptional stalking skills.