I have a Mod 19, 2 1/2", which shoots about 6" low at 25 yards with the rear sight screwed up about as far as I can get it. The sight leaf extends above the (rounded out) bottom of the sight by .0149". Can you tell me if this the correct location to measure it, and what height I would need to replace this with?

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H Richard
SWCA1967 SWHF244

I have a Mod 19, 2 1/2", which shoots about 6" low at 25 yards with the rear sight screwed up about as far as I can get it. The sight leaf extends above the (rounded out) bottom of the sight by .0149". Can you tell me if this the correct location to measure it, and what height I would need to replace this with?

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H Richard
SWCA1967 SWHF244

According to the formula, you need about .032 additional rear sight. However I would go for a bit more to give you some additional adjustment.

Formula is: Distance to target divided by sight radius. Then divide result into correction needed. All in inchs.

25yds=900inchs. Divided by 4.75 [my guess on sight radius] inchs is 189. 6 inchs [amount of correction needed] divided by 189 is .032.

Sight blade measurement--using windage screw move rear sigt to one side or other. I measure the blade with a caliper when I can see blade height. I am not sure what S&W uses, so ask when you call parts dept for blade.

This formula is not direction specific--works on up/down/left/right etc.

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the world is round everywhere

What bullet weight are you using? You might want to try a heavier weight bullet before you change the sight.

H Richard.

Sounds like someone has filed the rear sight blade from your figure. Even a .126 blade should protrude about .075 above the rear sight base.

To your original question, the rear blade for a 2 1/2" M-19 should be a .160, just measured mine. You will need a staking tool (lately S&W has used a center punch instead of a staking punch), a spanner for the windage nut (split screwdriver bit), and a rear sight blade kit. All is available from Brownell's, and the kit from S&W. The kit from S&W has an instruction sheet. Be sure to order two each windage screw plungers and springs as the first time you are certain to lose at least one plunger/spring set. Frequently the old windage screw will be burred so the original spring/plunger cannot be salvaged.

You can get either a white outline or plain blade. If you get the W/O be careful with solvents on it as the W/O is only painted on and many solvents will remove it.

BTW, ArgMauser is absolutely correct, too light a bullet will change POI considerably. From a 110 gr to 200 gr will make about 12" or even more difference at 25 yds. The factory targets .38/.357 revolvers with 158 gr bullets. Unless you bought it new it sounds like the previous owner may have been using a 180-200 gr load and adjusted/modified the sights accordingly.

Thanks. I bought the gun used, but it was literally unfired. It's a -4, P & R. It had finish problems as the prior owner had it in a gun case when they had a fire, and it got "damp" and the bluing was spotted and a few tiny spots of rust. I bought it for just over $200 due to this condition. I had a metaloy finish put on it, and ground the groves out of the trigger and polished it out. I had metaloy leave the front sight and base black, so the full top is flat balck sighting.

I'm familiar with changing out a blade on a rear sight, and yes there are already a couple of the tiny plungers are already somewhere in my reloading room, never to be found again. I made my own spanner for sight removal. A small old scredriver & a dremmel and about ten minutes. Is there a better way to remove the blade other than inside a large clear plastic bag?

When I first shot it, it grouped great, but about 8-10" low with .38 plus P 158 gr. at 10 yards. I intend to use it with 140 gr Sierra JHP's, at about 1400 fps, so I know it would shoot even lower. I do not believe the blade has been swapped out or filed on.

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H Richard
SWCA1967 SWHF244

Your measurement of how much rear blade sticks up above the sight base seems odd. I measured one of mine. A .160 sticks out of the base .133". Flat area of base to top of blade. If you run the blade all the way to the side you can measure the height of the actual blade.

Do you have a decimal point error in your 0.0149" measurement listed above? 0.015" is not enough to reach from the concave part of the sight base to the bottom of the notch, much less the top of the blade.

Blade height is just that - the distance from the top of the blade to its bottom. It's very easily measured when the blade is out of the sight body. If you screw the blade to the left side, you can make a pretty good estimation using calipers.

Buck

Yes, the decimal point is too far over. I was able to get the sight just barely out of the left side, and the overall measurement is .134. So it looks like I need another .026 which should make things alright.

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H Richard
SWCA1967 SWHF244

So a .160 blade should get you close. There is also a .196, not usually necessary. When you're changing the blade, if you orient the windage plunger so the plunger is under (and retained by) the blade, the process is much easier as you slide the blade in and out.

Hi!!!
I joined the forums because even though I am not a collector, I like certain classic guns more than the modern ones. I recently acquired a S&W Model 19-3, Blued, 2-1/2" recessed cylinder. Rear sight (blade height) is 0.146".
The front sight was DESTROYED completely by the previous owner. I understand this gun has the front sight as a one-piece unit, (machined in place) so replacement cannot be done by removing any pins and exchanging blades. I have found an UNEARTHLY amount of information in these forums but there is something I have NOT been able to find.
It is my intention to install an original ramp front sight without the RED insert. Some people mention 0.126" rear matches to 0.250" front; 0.160" rear matches to 0.300" front; BUT nothing regarding a match to a 0.146" rear sight on a 2-1/2" M19.


I have a Model 14 K-38 in 6" with a 0.126" rear and a Patridge front, but I'm NOT touching that one to remove sights to try on the Model 19.


Does anybody know what is the ORIGINAL blade height to match a 0.146" rear sight on a 2-1/2" M 19??


Thank you.


Robert

Got the following information from Colin H. @ Smith & Wesson customer service after sending an email with the revolver's information and Serial Number:


REAR Sight is 0.146" and FRONT Sight is 0.228"....... does it seem STRANGE????


For informational purposes.


Robert