NEED SIGHTING HELP

[hortonstn]

i 2002 i built a chambers hanes kit 38"getz barrel c weight 54 cal
i love this rifle, i have never set down and tried to get the sights where i want them. i really hate to change the rear but the ft is not a problem. i will try to explain what i have and if anyone has an idea of what i need to do let me know
i'm trying to set this up for a 60 yd target heres the details
measured from the top flat, rear sight is 8" in ft of the bp.
rear sight measures .202. top of sight to bottom of v is .121
ft sight measures.288 tall
any advise would be appreciated
paul

[Dennis Glazener]

The best way to regulate the sights is to shoot at a large paper target at 25 yards. Normally all my rifles have been close as far as wind-age but normally they shoot low. I take a file with me and keep filing off the front sight until I am on target as far as vertical. After getting it on target at 25 try it at whatever yardage you wish to have it shoot dead on. That front sight sounds too high to me.
Dennis

[Dphariss]

I am not sure you understand the process. The height of the sights is basically meaningless in the context of where the bullet strikes at a specific distance. Kentucky rifle sights are always filed to adjust the impact point vertically.
Where the bullet is currently impacting the target at 60 yards will tell you what to do with the front and rear sights to bring it to "zero".
Modern factory made firearms use specific height sights since the barrels are all the same and are placed at the same point on the barrel.

If you know what the ball is striking at 60 yards by shooting 5 shots then measuring from the aiming point to the center of the group. The giving the distance from the rear sight notch to rear of the front sight blade you can calculate the amount to remove from one sight or the other. Reducing the height of the front to raise the impact or reducing the rear sight to move the impact down.

Formula:
Sight radius times the amount the impact is to be moved divided by the target distance in inches (yards times 36).

At 60 yards with a 34" sight radius move the sight .016" to get 1" change at the target.

34*1/(60*36)= .0157"

This will work for any sight radius and any distance.

Note. The rifle needs to be tested and an accurate load determined BEFORE adjusting the sights the final time. Final adjustment needs to be done with the most accurate load. In good conditions a good shot should shoot into 3/4 to 1 1/4" at 60 yards.
But this requires experimenting with the load and most rifles are very picky as to the way they are rested and where along the length of the barrel.
Depending on where the rifle is rested the impact point can easily change 4+ inches at 65 yards. Rested 5" from the muzzle shot prone or off a bench my 50 caliber shoots 1.4" high at 65 yards.
With a angled plank rest, shooter on his knees on the ground, rifle rested on a vertical plank, shooter supported by an angled plank that is the brace for the vertical, rifle rested 29" from the muzzle it shoots 4" high at the same distance with the same load.
If shooting a match you need to understand the rules and use zero the rifle according to these rules.

Dan

[Lucky R A]

    You don't need a bunch of mathematical formula, unless you like exercises in math.  What you need is a hammer, a brass drift punch, a file and a plastic coffee can lid with a slot cut in it the size of your front sight blade.  A benchrest and some sandbags are also needed.  Shoot your rifle at 25 yards and shoot 5 shots like Dan said.  You can then determine how to move the sights to put the point of impact where you want it.  Cutting the front sight down is most common as most front sights are a bit high.  If this is the case place the slot in the coffee can lid over the front sight and then file a small amount of the sight off, (the coffee can lid protects your nicely finished barrel from the file when you slip).  If you have to cut the rear sight down then again protect the barrel while you file, you may have to deepen the rear sight notch, so in this case you will also need a file to cut the notch. You can adjust windage by moving the rear sight in the direction you want the bullet impact to move, the front sight is moved in the opposite direction.  I usually sight my guns in about 1/2 -3/4" high at 25 yards and you are good for most shots out to 75 yards.   Good luck...Ron

[Don Getz]

Paul........you haven't given us enough info about your gun and how it shoots.    Does the gun group well at any range?
and, if so, at what range?    You must first get it shooting fairly well at some given range, then using that same load, ball, patch, etc., shoot it at 60 yards and see where it is shooting, then adjust the sights accordingly.   Forget about the math,
shoot it.............Don

[Roger Fisher]

Paul........you haven't given us enough info about your gun and how it shoots.    Does the gun group well at any range?
and, if so, at what range?    You must first get it shooting fairly well at some given range, then using that same load, ball, patch, etc., shoot it at 60 yards and see where it is shooting, then adjust the sights accordingly.   Forget about the math,
shoot it.............Don

Exactly !

[hortonstn]

thanks for the help the first nice day i get i will be at the range
paul

[SCLoyalist]

Hort., the sight radius (distance between front and rear sights) for your rifle is about 28" (38" overall length - 8" bp to rear sight distance - 2" the front sight is behind the muzzle).    For every 1/1000" you alter the front or rear sight by drifting or filing, at 60 yds (or 2160 inches) you will change the point of impact by:
2160/28 *.001 inch = .077"
If, for a given load and sight picture, you are hitting 2" high and 4" right at 60 yds, then could make the correction by altering the front sight by filing off about 26/1000 (slightly less than 1/32") of an inch to take care of the vertical error, and could correct the lateral error by drifting the rear sight by 52/1000" (or approx 3/64")  to the left.

I think the convention, for appearance sake as much as anything, is to center the front sight on the barrel flat and use front sight height to adjust vertical point of impact, and to use the rear sight to control lateral adjustments by drifting.    Remember that lowering the front sight height will make the bullets hit higher, raising front height (e.g. through a taller blade) will move the holes lower, drifting front sight left or the rear sight right moves the hits to the right,  etc.   Don't file anything until you're sure you don't need that metal anymore.   Once you see how far off you're hitting, the math might give you an idea how much to alter the sights so you can zero in quicker.   However, it does eventually come down to trial and error to verify you're done.   Good Luck.
 
PS March 2011 MuzZleBlasts has an article on sighting in.

[Daryl]

I've been playing this game for a lot of years, sighting in iron sighted rifles, ML's and others. I have never resorted to mathematics and measuring with calipers to find what is needed. File a bit and shoot, file a bit and shoot, drift a bit and shoot - works every time.

If math is your game, then have at it, I guess, but I'll have been sighted in perfectly while you are still measuring & figuring, then probably making a mistake and fussing abotu the math.   It is far easier to file off a bit, then test, file, test, than it is to figure the amound, measure it out and scribe it, then file to the mark, check, file, mark, etc.  You'll need an accurate set of calipers and a magnifyiing glass & then probably end up filing and shooting, filing and shooting the way 99% do it.

With a ML, a quarter inch at that distance isn't critical, except maybe a bullseye shoot off bags & it will take 6 to 10, 5 shot groups to see that the suspected 1/4" is actually a true 1/4" error - which is then easily adjusted - another swipe with a file - going up 5gr. might do it as well, if it's elevation needed. (I never go down in charge - HA!)

[hortonstn]

thanks again, just so you all know i hate math....
paul

[Standing Bear]

To all of you seat of the pants no math sighter inners.  

I do the math to get close to where needed without going too far and having to file on the other sight and then sawing it off too far (exaggeration to make a point ).  Do I file .040 and find out I only needed .030?  Do I make 15 strokes with the file and shoot 5 shots to see that there was almost no change in POI?

There is no math or effort in using the formula with a calculator just plug in to Dphariss' equation and push go.  Then if the sight needs to be moved .160" no problem marking .150 on the sight, grind to that and then trial and error getting the other .010".  Yea, .160" seems like a bunch but my latest set of sights are 1/2" high.  

Even with clicker sights you can predict number of clicks to raise POI when going from 50 yards to 100 yards.

Hey, just give us the distance between sights and the movement needed at what distance and we'll do the math.

[Daryl]

Tcomp - practise filing for 40 years and you get to have a feel for it. Never trusted math, anyway.  .010" makes little difference in my shooting with iron sights.  For long range shooting where .010" does make a difference, I am using adjustable sights that allow .010" adjustments or finer.

[Gene Carrell]

My range  box contains a brass hammer, nylon drift and several small files. Always  has worked. Shoot and file or drift. Shoot and ...

[Standing Bear]

Go ahead.  I like to get sight regulation done and then practice shooting offhand.  Just atating that it really is easy, much faster and allows more fun with the same amount of ammo.

Don't trust math?  Really?