I need to move my pattern 4" to the right on my 450bpe. How many thousandths do I need to move my rear sight. I changed my front sight to a taller one, and jj had to resolder the wedge. this moved my pattern.

That is a simple Trig function. Figure the angle and the distance and the sight radius. It has been a long time since I did trig so tap a little to the right and shoot then tap a little and shoot until you are there.

Sam

Tap or tap tap to the right. Much easier to take the brass punch to the range and fix it as you shoot it.

ND,

I've done this twice. First step is to check to see if you have any set screws that must be loosened before you start to tap to the right.

One of my doubles does not have set screws, but, rather, screws that fix the back sight firmly to the rib. I'll be sending it off to get a new back sight made that I can drift if needed.

Regards, Tim

I have a slot blade screw recessed flush under the second folding leaf. It doesn't appear to have any room for drift around the head. That's why I asked my innitial question. If it only needs to move a few thousanths, it should drift. If more is needed, I will have to mill a slot for the screw.
Thanks, ND

Isn't this screw a jam screw to hold the sight in place? It should not be threaded into the rib.

To move a group;
1. measure the distance between the front and rear sights.
2. Multiply the sight distance times the distance the group is to be moved.
3. Divide the answer by the distance to the target in inches.
4. this is the distance the sight is to be moves.

Thanks! My last trig class was in the 1970's, I couldn't remember how to set up the equation. I appreciate all the input.
Thanks, ND

Nitrodave:
For a usual distance between front and rear sights of about 20", and if you are shooting at 50 yards, a 1 mm (0,04 inches) displacement of your rear sight to the right will move your point of impact to the right a tad under 4 inches; that will be a good starting point.

Antonio

Just tap it over a bit at a time until you get it right, the mathamatical equasion is flawed all to hell by barrel viberations..A brass punch and a hammer is the way to do it, just go a tad at a time..it works every time and if you go to far then knock'er back....

Thanks guys! I got it right This Wednesday. Tapped it too the right, then shot. It was then 4" to the right. Tapped it back left a little, and now I am dead on at 100yds and 2" high at 50yds. I can pull down to leave about 1/2 of the bead showing at 50yds and hit dead on. I am getting about 1" spread at 50 and 2.5" spread at 100.
Thanks, ND

You have an exceptionally accurate double rifle, but then most of Butchs guns shoot like that..

Ray,
although my Searcy .470 shoots as well, this gun is a 1889 Joseph Harkom 450BPE. It can still be viewed on Champlin's web page. I bought this gun from George about a year ago. It hadn't been shot much as the chambers were tight. I have everything running right now.
I will be using it this year at our annual "Dangerous Doe Hunt".