36 cal Sight In

[Kamu]

I built a traditions 36 cal rifle. I had to replace the rear sight. I am shooting 40 grains of 3f black powder. It is shooting 4 1/2-5 inches low at 30 yards. I have 1/4 inch left of the front sight to file down to bring the POI up. My question is do I have enough front sight left to bring it up. Any recommendations would be great.

 

[don hepler]

There are online sight correction calculators but I can't remember the web site. However, due to front sight getting too low, you'd have to raise the rear sight. Seeing, that you've already changed that, your only other option, would be to find a taller rear sight.

Okay, I found it. Google sight calculator and try the one from Brownells.

 

[Spikebuck]

Just to get an idea, blacken a portion of the front sight that is remaining with a felt-tip marker (it can be cleaned off), or if the sight is already black, use some white nail polish or something. Use the bottom of that black as the top of your sight. You will probably need to hold off the the side of the bull a bit if the front sight is covering it, but you're only testing elevation anyway. Shoot a few rounds. By doing this, it will tell you if you had the sight filed down to that level, where would you be hitting up and down.

A quarter inch of front sight is a lot. Front sights are cheap if you need to start over with a taller rear sight. Fixed rear sights are rather cheap too. Track of the Wolf carries all kinds of them.

 

[Zonie]

Welcome to the forum.

To give you a value for the amount of front sight that would need to be removed, I need the measurement of the distance between the front and rear sight.

To save you some time, I can give you the factor to be multiplied by the distance between the front and rear sight but I have to pick one of your values to base it on.

I guess I will pick the 4 1/2 inch value.

You say the distance to the target is 30 yards.
30 yards X 3 = 90 feet.
90 feet X 12 = 1080 inches.
4 1/2" error/1080" = .0042

This is the factor that you would multiply times the distance between the sight.

Let's say the distance was 26 inches.

26 inches times the .0042 factor = .109" or about .016 (1/64") less than 1/8".

That would leave your front sight around .142 inches tall.

Because material is hard to put back on, I'd suggest that you should take the gun to the range and shoot several more groups to make certain your 4 1/2 inch error is accurate.

It's also a good idea to do the final filing at the range, firing a few shots, filing off a little, firing a few shots, filing off a little...

You get the idea.

 

[hanshi]

Welcome to the forum, Kamu.

Replacing sights is no big deal; I've had to do it a couple of times and it is not difficult.

 

[coloradoclyde]

I'd just go to the range and file and shoot....I have a clamp on vise to hold the muzzle in...I color the surface to be filed with a sharpie...That way I file evenly and don't get the profile all screwed up. Take a little off and shoot a group...Repeat, reducing the filing as you get close....I stop short of my goal and finish the final touch up on another day after I have shot the gun some....

I also plug the muzzle when filing....

 

[Kamu]

Thanks all.. I really like the idea of choking up on the site to see where I might end up at, and ill do it at the range and shoot a few between filing. Worst case i'll replace both sights if need be..

 

[Bent Sight]

Zonie is on the right track. The sight error correction formula is: Error in inches x Sight Radius in inches/Distance to target in inches = Sight Correction in inches.

Example 1: If I had a rifle with a sight radius of 19.25" and a round ball hit 4" low at a distance of 30 yards, the formula would look like: 19.25" x 4"/1080" = 0.0712962" or 0.071" correction. I would have to file 0.071" off the top of the front sight.

Example 2: If the round ball hit 3" left at the same distance, the formula would look like: 19.25" x 3"/1080" = 0.534722" or 0.053". I would have to tap the rear sight 0.053" to the right to correct.

If you think you need to correct a sight, move or file it by 1/2 the amount you calculated with the formula and fire a group. I suggest shooting at the maximum distance you feel you will shoot the rifle, i.e. 75 yards or 100 yards. Check the distance the center of the group is hitting low and plug the value into the formula. It is easier to file material off the front sight than to add material. I know that from experience.

 

[Kamu]

My sight distance is 24.75 inch

 

[Bent Sight]

My sight distance is 24.75 inch

24.75" x 4.5"/1080" = 0.103125". The value you would have to remove from the top of the front sight is 0.103" or 1/10". I suggest removing one half that value and shooting at 75 or 100 yards before filing any more off the top of the front sight.

I also suggest shooting groups with the maximum load you intend to shoot in the rifle. The difference in the Point of Impact at 100 yards with my T/C Renegade is 10-1/2" when shooting groups with 40g of Pyrodex and 70g of Pyrodex.

 

[Kamu]

Thanks all...

 

[Larry (Omaha)]

Kamu, (Mirage)
Another thought: I personally do not like low sights as mirage can occur when it is warm or sunny. If you want to minimize mirage, you are already as low as I would go. Again this is just my preference.
Flintlocklar
:wink:

 

[hanshi]

I will mention that most sights on original longrifles were very, very low and small.

 

[Black Jaque Janaviac]

Kamu,

You're in a better spot than I. I've had a number of guns that shot high. I screwed the adjustable rear sight down as tight as it would go and they still shot high. Ended up with a new front bead that looks like the Eiffel Tower.

I vote for shooting a few shots with the front sight protruding high above the rear sight to see if you have enough sight to work with.

 

[Tom Compton]

I built a traditions 36 cal rifle. I had to replace the rear sight. I am shooting 40 grains of 3f black powder. It is shooting 4 1/2-5 inches low at 30 yards. I have 1/4 inch left of the front sight to file down to bring the POI up. My question is do I have enough front sight left to bring it up. Any recommendations would be great.

Sounds like the replacement rear sight was too low or you are using a “fine” bead with the top of the front sight as low in the rear notch as possible.

On a straight barrel using a “pistol” sight picture the front sight and the top of the notch of the rear sight are often the same or near the same height from the barrel.

I personally wouldn’t file the front sight any further. Either change your sight picture or replace the rear sight with a higher one.
TC

 

[Billnpatti]

I built a traditions 36 cal rifle. I had to replace the rear sight. I am shooting 40 grains of 3f black powder. It is shooting 4 1/2-5 inches low at 30 yards. I have 1/4 inch left of the front sight to file down to bring the POI up. My question is do I have enough front sight left to bring it up. Any recommendations would be great.

You need to measure the distance from your rear sight to your front sight in inches. Divide this number by 1080 (the distance in inches for 30 yards). Then multiply by the number of inches you want to raise your POI in inches. In your case, you would multiply by 5 inches. Your answer will be the amount of metal in inches you will need to remove from your front sight to bring your POI up to the center of the bulls eye. Your answer should be in the neighborhood of .093 inches or 93 thousandths of an inch. I used a guess of 20 inches for the measurement of the distance between your front and rear sight. When you use the actual distance between your sights, you will get a different answer but it should be in the same neighborhood as mine.