rear sight out of plumb

[Old Jim]

And to further the topic,

does anyone remember why most trapdoor rifles had a rear-sight that leaned over to the side, when elevated to the higher settings?, leaving us with a rear-sight NOT square with the front sight???????

[Lumpy Grits]

For 'drift'.
That sight 'tilt' works, if you only shoot one load/weight in the same rifle.
Both of my Shiloh's(.45-70 & .45-90)are set for a mechanical "O" at 500yds.
Liv'n in the Mojave Desert, it sometimes takes awhile to get just the 'rite' day to make this setting.
Gary

[bobw]

precession ole Jim

[Brownie Nash]

The the sight leans to the left is to compensate for what is called spinn drift.Right handed twist barrells drift to the right. This is what I always believed to be correct. My two cents worth.

Regards

Brownie

[chaneylake]

here is how I checked tang site for plumb

1st I leveled barrel from chamber to front site
2nd I placed a level on barrel perpendicular aka cross ways
3rd I hung a plumb line about 24 feet from rear tang sight
with tang sight bottomed out I positioned it on plumb string and proceeded to raise rear sight
I did this 3 times on Saturday and once on Sunday morning and rear tang sight appears to be plumb with the barrel

from the bench firing at 100 yards with windage set on "zero" I fired 2 groups of 10, these groups averaged 1.9" to the right of center of bullseye

I then fired 2 groups of 10 at 200 yards, these groups averaged 6.9" to the right of bullseye

there was a very light incoming wind at about 10:30 at a maximum of 2-3mph, wind was so light that tree limbs were not moving and you had to look at tall grass to see if it was even blowing

my question is this, if the rear sight is plumb shouldn't the 200 yard groups be only 4" to the right of center if all conditions stayed the same

[Brownie Nash]

This is how I install sights on my guns. I first level the action ( verticle) Then check the barrel level, if the gunsmith did his job when he cut the dovetail it will be level. Then I check the vienier sight with a machinest level or a level on a quality combination square. then shim or file site base to level vernier sight. If I am sighting in a lever gun I want it to hit 1" left of center at 100yds. (good for 600yds or less) If I am sighting in a single shot to use over 600yds I want it to hit 2" left of center at 100yds. Remember this is how I do it right or wrong. My free advice for the day and free advice is worth what you paid for it.

[Kurt]

This is were a wind gauge sight comes in if you shoot matches with the rifle when shooting sighters when allowed I take note how the mirage is moving. I set the tang on zero and adjust the front sight. That way if the wind starts to fish tail I always know my zero wind setting.
In your case what I would do if your rifle has a spirit level on the front I would use it to plumb the tang because that is what you will use when you shoot. If you want to get the tang zero drive your front sight in the direction you want to hit. With you only being off 1"@100 yards you wont move the front much more then 1 or 2 hair width or take the base off and use some 220 emery and take off a swipe or two with the cloth laying on plate glass and check where the impact is following a shot. I do this at the range if the rifle does not have a wind gauge front sight. That base will always stay with the rifle.
With these rifles just a whisper of a slight breeze that will just raise a feather hanging on thread will change the impact at 200 yds. It might be on the back of your neck where you are but that does not mean it is the same down range.

Kurt

[Lumpy Grits]

Did you make sure the front sight isn't moving in the dovetail.
Any side to side play in the mast of the tang sight when up in shooting position?
Make sure the screw that holds that mast to the base is tight.
Gary

[chaneylake]

Did you make sure the front sight isn't moving in the dovetail.
Any side to side play in the mast of the tang sight when up in shooting position?
Make sure the screw that holds that mast to the base is tight.
Gary

front sight is plenty tight
zero side play in mast of tang
screws are tight

I have just having a difficult time in believing that such a light wind that I was shooting in on Sunday would give me that much drift

is the drift at 200 yards twice the drift at 100 yards?

[Old Jim]

If your rifle is capable of 2" grouping @ 100 yds, read that as MOA rifle, then 4" @ 200 yds is possible. Then again, it's possible your rifle/load is NOT a MOA combination. Whereupon, even a "slight" breeze/windy condition can appear to scatter you bullet-holes around.

Also, the wind conditions at the muzzle of the rifle may not be the same @ 200,300, 400 yds. downrange.

Just tryin' to add something here. I do not know it all!