Howdy!

I recently custom fit an LCR fiber-optic front sight onto a 4" 15-3 (details here). For the rear, I went with a .160 blade. I tried to sight it in tonight but there's not enough adjustment in the rear; with the sight bottomed out and the dot centered in the rear blade, I'm still hitting 3-4" high at 10 yards. To hit POA, I have to cut the dot in half with the bottom of the notch.

Am I right in thinking that I need a shorter blade to bring down the POI? Any guesses on what height to get?

Also, I understand that the measurement is for the height of the blade. How does that compare to the notch? Does a .160" have a deeper notch than a .126"? Or is the notch the same and it just shifts up or down based on the height of the blade?

I would throw a .146 blade in there and it should put you in the ballpark. The model 15 originally came with a .106 blade... I think. Although I put a .126 white outline rear blade in my 15-2 with the factory front sight, it's still fine when it's ran down almost all the way. With your taller new front sight (at least it looks to be a hair taller than the original), the .146 rear blade would probably be your best bet.
I also think that the depth of the notch is more shallow on the .106 and gets deeper as the blade height gets taller.

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USAF AMMO

Just shoot 110g jhps.

On the factory rear blades, the bottom of the notch is always at the same level, and gets deeper as the sight blade gets taller.

I trigged it out and it shows that with 3" high at 10 yds. you have a discrepancy of .050. With 4" high you have a difference of .066. The bottom of the notch will not go down, so you need a taller front sight to lower the muzzle. You want to keep the deep notch of the .160 so you don't have to cut off the bottom of the dot when aiming.

Are you totally sure that the notches are always the same level? I grabbed two pictures off of eBay - one is a .106 and one is .146. On the shorter one, the notch drops into the body of the sight. On the other, it's above it.

Actually, I just verified using the .160 and .106 I have. Measuring from the bottom of the "barrel" that the screw goes through to the bottom of the notch:

.160 measures .271
.106 measures .23

So the notch is lower.

You are right. I should have done my research better before posting. I apologize for giving wrong information.

At any rate, we know how much it needs to change. I have several rear sight blades. Would you like me to send you one of your choice?

I'll shoot you a PM. Thanks!

Sent from my STV100-1 using Tapatalk

Well, that was quite cornfusing. Now I have a headache!

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NRA Benefactor

Waiting to hear back from Toolguy, but my hope is to pick up a few different length blades. If I do, I'll measure and post dimensions for each (how tall it is overall, blade height, notch depth, notch width, etc). It's data that you would think lives somewhere but I've never turned it up.

I'll send you one of each in the interest of helping everyone on the forums. I don't know if they will all be white outline or not. PM me your mailing address and I'll get them out sometime this week.

matteekay,

I would order three different heights, a few screws and nuts and this way you have them and can dial it in. Which ever extra's you wind up with can always be used on others guns. They are certainly not expensive and they do come in handy. Down the road you can always modify them, paint lines on them, etc.

BTW,
There is actually a published list somewhere here on the Forum of which Revolvers and barrel lengths came with what sight heights, HOWEVER for SOME shooters the Factory height does not suite their vision. I do not quite understand how two different people can see the same sight picture so differently, but it is not uncommon. I have two friends that had to replace their stock rear sight blades with different heights because they ran out of adjustment. Funny, since for me THEIR guns shot spot-on.

Since the freight will probably cost more than the blade, now is your opportunity to get different ones since the freight will be paid for anyway.

Part of the formula is bullet weight and velocity of said bullet, which can vary the recoil a lot, depending on the load. Another element is grip strength and how tight you hold the gun. Recoil (muzzle rise) begins as soon as the bullet starts to move out of the case. There are other variables as well, such as barrel length and powder burn rate. Normally the barrel starts out pointing under the target and is sighted in to where the bullet comes out of the barrel just as the barrel moves upward even with the target. This amount can be from almost nothing to quite a lot.

PM'd Toolguy. Thank you again for the help!

chief38, I'm going to do that. Gotta find a source for windage screws that isn't charging $15 per (seriously, it's insane). I'll poke around and see what's out there.

Is this what you're talking about? The problem with this list is that it doesn't say how tall the front sight is.

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USAF AMMO

Try this:

Sight Calculator


Or this:

I finally got all the sight data compiled into one thread. See what else you think I should add!

Revolver Rear Sight Blade Information Thread