How Much Higher Does My Front Sight Need To Be?

[Silver Jack Hammer]

I've just tested my new Colt's 1860 and it hits 19" high at 25 yards. How much higher should my new front sight be? I'll be filing out a new front sight to be installed, I'd like to make sure my new front sight is going to be high enough.

[Nueces]

The calculation goes like this: (19 inches) / (range in inches = 25 yds x 36 inches per yard = 900 inches) all times your sight radius in inches = front sight height change.

So multiply your sight radius by 0.021 to get the height change. So, for a 10" sight radius, your front sight needs 0.21" more height.

[Omnivore]

Nueces has it. Listen to Nueces.

I think of the distance to the target as a number of sight radii. A 900 inch distance divided by our theoretical ten inch sight radius is a distance of 90 sight radii. 19"/90 = .211"

Now you can see that it's basic triangulation; for every sight radius in distance to the target, the point of impact diverges another .211" from the point of aim. It's simple multiplication or division then, depending on whether you're figuring it from the gun to the distance of the target, or from the target back to the gun.

So you have all you need but first you'll have to cock that hammer and measure the distance between sights, then plug that number in instead of 10. My Pietta '60 Army for example has a SR of 10.5", so 900 inches distance is equal to 85.71 sight radii and 19"/85.71 = .222". That's the increase in sight height you would need if your SR is 10.5"

Make the new sight a bit taller still, and then bring a file to the range to tweak it in.

Of course all this assumes that you've settled on a load that shoots as accurate as you need. The point of impact changes a little bit if you're shooting a heavier or lighter bullet, or using a different amount of powder.

I have the same problem with my Pietta Colt Army. Pretty much all Colts and Colt repros shoot waaay high at those distances. I'm still torn on whether to cut a dovetail for a drift adjustable front sight, or if I want to make something similar to the original sight. The dovetail does make more practical sense, that is, if practical sense has anything to do with using this 150+ year old technology.

[Texantothecore]

I assume that calculation would also work to estimate the filing down of the notch of the hammer?

[Nueces]

I assume that calculation would also work to estimate the filing down of the notch of the hammer?

Yessir, same calculation applies to front or rear sight and also to windage adjustments.

[Texantothecore]

Thanks for the info. I will be using this next week to modify the hammer on my 51 Navy and I am really looking forward to poa shooting at full power at 25 and 50 yards.

And yes, I do have 2 spare hammers. Lol.

[Silver Jack Hammer]

Texantothecore, I just knock off the front sight and fashion a new one from the wing of a brass wing nut. The front sights are easy to remove, just knock them out by tapping from the loud end of the gun toward the handle end.

[Texantothecore]

Texantothecore, I just knock off the front sight and fashion a new one from the wing of a brass wing nut. The front sights are easy to remove, just knock them out by tapping from the loud end of the gun toward the handle end.
I decided, after serious consideration of modifying the front sight, to modify the hammer. I will probably end up with hammers for 25, 50 and possibly 100 yards just for laughs. The hammer change is pretty quickly done and I generally know before I go to the range what distance I will be shooting. I may still change the front sight but I am going to try this first.

[rondog]

Or just aim at the belt buckle.....

[Texantothecore]

Or just aim at the belt buckle.....

I'll be doing that too. One of the techniques I'm going to use is to pound one inch stakes in the ground at random unmeasured distances and shoot at those. The gun is well worth the effort to master it so I will be doing a lot of belt buckle shooting.

[Silver Jack Hammer]

Different hammers for different distances. What a great idea Texantothecore.

[DerekP Houston]

The calculation goes like this: (19 inches) / (range in inches = 25 yds x 36 inches per yard = 900 inches) all times your sight radius in inches = front sight height change.

So multiply your sight radius by 0.021 to get the height change. So, for a 10" sight radius, your front sight needs 0.21" more height.

Wow, I'm copying that formula down for future reference. Thanks!

[quail4jake]

Good advice, follow that formula to find sight alteration dimension. My Pietta 1860 had the same sight issue and when I discovered that it delivers a 2" group at 25 yards with 32 gr. of Swiss FFFg my interest in making a useful sight adjustment was peaked! I seem to recall about .200" correction; pull the old sight out and get filin' on a piece of .125 thick brass to make a nice new sight of the height needed plus a little so you can file down to hit smack on or an inch or two high at 25 yds. Fit and press the new sight into the keyway and go to the range! Don't bother grinding the HARDENED hammer; you'll just get the thing all assed up and foul up the mechanics of the hammer and nipple. If you want to go bling, cut a wedge out of a silver eagle or other thick coin and make a sight out of that! Now you got de look and be blingin', yo!

[Motor]

Yep good simple formula. When I first incountered this problem I used trigonometry to figure it out then while "messing around" with the numbers found the simple "taper per inch" formula.

It doesn't take into consideration bullet drop but if you are like most of us going from an existing POI it works every time. All you need is a reasonably good measurement of the distance between the front and rear sights.

Motor

[jjarrell]

I had to install a higher front blade after going to a longer barrel. Lyman 57SML rear was adjusted all the way down and I was still 4.5" high at 50 yds.