586 sight problem...

[carguychris]

Howdy all,

I took my new/old 6"-barrel 586 out to the range on Friday for the first time.

I soon discovered a little, shall we say, issue with the sights.

Set up a silhouette target at 15 yds, loaded up a cylinder of .357Mag ammo, cocked it SA, lined up the sights on the X-ring, BANG...

My first thought... Where's the hole?!? Second thought... there it is... about 18" low! WTF!! I'm not THAT bad of a shot!

Lined up more carefully and took 3 more shots. The good news... I shot about a 1.5" group! The bad news... it's still 18" low, next to the first hole!

I'm thinking OK, got to be the sights. I wound up finally getting the revolver to shoot to POA after adjusting the sights up 21 clicks! I went home intending to ask what's wrong with my 586, but I happen upon this little blurb in the manual...

Oh.

My gun has the tall Patridge front sight. It's built to shoot low.

But I don't want a .357 that shoots 18" low. I want it to shoot to POA, and I want more useful upwards adjustment for long-range targets. The rear sight's elevation adjustment is almost maxed out to get it to shoot to POA at short range!

What should I do...

1) Install a .160" rear sight slide like the manual says? <STRIKE>If so, how is it installed? I can't seem to figure out how to remove it</STRIKE>. {Never mind, found it in the FAQs...}

2) Install a different front sight? I've been tempted to put a gold-bead or fiber-optic front sight on this gun anyway. Would it work with the (presumably) .146" rear sight slide?

3) ????

Any thoughts are appreciated. The idea of a gun designed to shoot low has still got me stumped...

 

[carguychris]

Howdy all,

I took my new/old 6"-barrel 586 out to the range on Friday for the first time.

I soon discovered a little, shall we say, issue with the sights.

Set up a silhouette target at 15 yds, loaded up a cylinder of .357Mag ammo, cocked it SA, lined up the sights on the X-ring, BANG...

My first thought... Where's the hole?!? Second thought... there it is... about 18" low! WTF!! I'm not THAT bad of a shot!

Lined up more carefully and took 3 more shots. The good news... I shot about a 1.5" group! The bad news... it's still 18" low, next to the first hole!

I'm thinking OK, got to be the sights. I wound up finally getting the revolver to shoot to POA after adjusting the sights up 21 clicks! I went home intending to ask what's wrong with my 586, but I happen upon this little blurb in the manual...

Oh.

My gun has the tall Patridge front sight. It's built to shoot low.

But I don't want a .357 that shoots 18" low. I want it to shoot to POA, and I want more useful upwards adjustment for long-range targets. The rear sight's elevation adjustment is almost maxed out to get it to shoot to POA at short range!

What should I do...

1) Install a .160" rear sight slide like the manual says? <STRIKE>If so, how is it installed? I can't seem to figure out how to remove it</STRIKE>. {Never mind, found it in the FAQs...}

2) Install a different front sight? I've been tempted to put a gold-bead or fiber-optic front sight on this gun anyway. Would it work with the (presumably) .146" rear sight slide?

3) ????

Any thoughts are appreciated. The idea of a gun designed to shoot low has still got me stumped...

 

[Joni_Lynn]

You'll either need a shorter front or taller rear or both.
The rear sight has a staked nut on the left side. You may be able to take it apart by winding the adjustment all the way to the left and then keep turning it until the nut snaps off or the threaded shaft pulls through the nut.
Now, in the head of the adjustment shaft, right side is the two (2) of the smallest parts that you'll ever lose and wish you hadn't.
A very small spring and an equally small plunger. They're what gives the sight it's clicks as you turn windage into it.
If you order a sight kit just order new ones so if/when you lose them you'll have another set.
You can restake the nut with a small punch or buy a proper staking tool.
When I do it, I run the nut down snug and then back up 1/4 turn and then stake it well.
Good luck!!!

 

[tomcatt51]

Do you have the means to measure the height of your front blade? Height of the patridge from the sight base to the top? It will be .228" or .243" or .278" I think. If it was mine I'd be looking at a SDM Fiber Optic front of suitable height to use a .160 rear. SDM FO fronts are available .250" or .300" tall.

Joni's right on about the rear sight proceedure but you can also remove the rear blade by drilling the staked (left) end of the windage screw with a 3/32" bit to remove the part the staking swelled, and just unscrewing the nut. You can then reuse the screw and nut if you loctite the nut. Can make life easier while you play with blade heights and if you want to enlarge or deepen the notch.

 

[Gun 4 Fun]

If it were mine, I'd simply file down the front sight a few thousands at a time. You can do this at the range. File the top off till you get POA located in the middle of the adjustment range of your rear sight, at your prefered shooting distance. Reblue the top of the blade with a good cold blue and coat with a light coating of oil. It's really easy to do, and can be acomplished in a short period of time.

 

[Guest]

To begin with your gun was "Sighted-in" at the Factory for 25 yards. and likely with a Center Hold - most common. I'd take it to the Sand Bags and the 25 yard line to see what you gun will do. You didn't say what "load" you were using but the Factory uses 158 grain ammo as the Standard for the .357 Magnum.

Shooting something like125 grain ammo can account for you showing much lower and that plus the shorter distance - well, give the Sand Bags and the 158 Grain ammo a try at 25 yards.

 

[bountyhunter]

Originally posted by carguychris:

1) Install a .160" rear sight slide like the manual says?

That is definitely the easiest. You can also cut the top of the front sight but that is NOT REVERSIBLE like changing the rear blade is.

HOWEVER: the 6" barrel gun has approxinately 8" sight radius, so shifting the point of impact 18" up at 25 yards requires a change of 0.36" at the sight height and that is a LOT. I would put on the tallest rear sight available and see what that does. You may need to shave the front sight too.

 

[bountyhunter]

Originally posted by KKG:


Shooting something like125 grain ammo can account for you showing much lower and that plus the shorter distance - well, give the Sand Bags and the 158 Grain ammo a try at 25 yards.

Lighter grain bullets do hit lower on target if they are loaded to about the same final velocity. Less mass, less powder equals less recoil so the muzzle's upward rotation is less at the point of the arc where the bullet leaves the barrel.

But, at shorter range the variance is LESS due to this effect.

In my experience, I have never seen a change of more than a few inches at 25 yards in going from 158 to 125 grain for comparable loadings.

BTW: that "neck hold" thing means that they shoot at the human silouette outline target and can aim at the neck instead of the center mass. The reason this is an advantage is that silouette is black and the black sights are lost against it so it's hard to sight. One of the best shooters we had shot a model 66 with aftermarket sights he could click up to do this. If you can aim at the neck, you align/level the sights on the tan background next to the neck and then just shift it over. The rest of us had to paint our sights to see them.

I shoot that target a lot and the neck is just about 18 inches above the X ring on it.

 

[tomcatt51]

Originally posted by bountyhunter:
HOWEVER: the 6" barrel gun has approxinately 8" sight radius, so shifting the point of impact 18" up at 25 yards requires a change of 0.36" at the sight height and that is a LOT.

Unless I've forgotten my fifth grade math, changing your POI 18" @ 75' (25 yds) on a gun with an 8" sight radius (6" barrel revolver) requires approx. a .013" change of the front or rear sight height. In this case, basically the difference between a .146" and a .160" rear blade.

 

[Joni_Lynn]

If only changing to that rear sight blade height the sight may still need to be all the way at the bottom of it's travel adjustment to sight in. I'd recommend enough of a change to allow the sight to have adjustment left in both directions.

 

[exSun]

Originally posted by tomcatt51:

Originally posted by bountyhunter:
HOWEVER: the 6" barrel gun has approxinately 8" sight radius, so shifting the point of impact 18" up at 25 yards requires a change of 0.36" at the sight height and that is a LOT.

Unless I've forgotten my fifth grade math, changing your POI 18" @ 75' (25 yds) on a gun with an 8" sight radius (6" barrel revolver) requires approx. a .013" change of the front or rear sight height. In this case, basically the difference between a .146" and a .160" rear blade.

Let's see. 18" is 0.5 yard. So you want a change in the ratio of
0.5yd/25yd = 0.020 . To change your sights in the same ratio, you need to move them 0.020 x 8" = 0.160" or so I think. Of course, math may have changed in the 40 years since I first studied triangles.

Chris

 

[tomcatt51]

Originally posted by exSun:

Originally posted by tomcatt51:

Originally posted by bountyhunter:
HOWEVER: the 6" barrel gun has approxinately 8" sight radius, so shifting the point of impact 18" up at 25 yards requires a change of 0.36" at the sight height and that is a LOT.

Unless I've forgotten my fifth grade math, changing your POI 18" @ 75' (25 yds) on a gun with an 8" sight radius (6" barrel revolver) requires approx. a .013" change of the front or rear sight height. In this case, basically the difference between a .146" and a .160" rear blade.

Let's see. 18" is 0.5 yard. So you want a change in the ratio of
0.5yd/25yd = 0.020 . To change your sights in the same ratio, you need to move them 0.020 x 8" = 0.160" or so I think. Of course, math may have changed in the 40 years since I first studied triangles.

Chris

Yep, brain fade, .160" to change POI 18" @ 25 yds.

 

[bountyhunter]

Originally posted by tomcatt51:

Originally posted by exSun:

Originally posted by tomcatt51:

Originally posted by bountyhunter:
HOWEVER: the 6" barrel gun has approxinately 8" sight radius, so shifting the point of impact 18" up at 25 yards requires a change of 0.36" at the sight height and that is a LOT.

Unless I've forgotten my fifth grade math, changing your POI 18" @ 75' (25 yds) on a gun with an 8" sight radius (6" barrel revolver) requires approx. a .013" change of the front or rear sight height. In this case, basically the difference between a .146" and a .160" rear blade.

Let's see. 18" is 0.5 yard. So you want a change in the ratio of
0.5yd/25yd = 0.020 . To change your sights in the same ratio, you need to move them 0.020 x 8" = 0.160" or so I think. Of course, math may have changed in the 40 years since I first studied triangles.

Chris

Yep, brain fade, .160" to change POI 18" @ 25 yds.

Calculator malfunction actually:

25 yards = 75 feet = 900 inches.

Sight radius is about 8"

ratio = 8/900 = 8.9 x 10-3

times 900 = 0.16 "

Yep, believe it or not the problem was a solar powered calculator that screws up on dark days.

0.16" is still a big chunk to raise the sight height. Going from the .146" blade to a .160" blade is only 0.014 which is LESS THAN 1/10 OF THAT MUCH.... so changing that blade will do very little.

 

[bountyhunter]

Originally posted by Joni_Lynn:
If only changing to that rear sight blade height the sight may still need to be all the way at the bottom of it's travel adjustment to sight in. I'd recommend enough of a change to allow the sight to have adjustment left in both directions.

Actually, it's hitting low so he has cranked the rear sight all the way up to get it close to POA.

 

[Joni_Lynn]

.............oops.
Sorry, I had forgotten it was low instead of high.

 

[Skip Sackett]

I have several M586 6" guns. I use them for PPC but none of them have the partridge front sight. I also use moderate 38spl rounds in this type of shooting, not 357mags.

If it were me I would use two different holds before I would make any changes in hardware. If the gun shoots well, as it seems to, wouldn't that be the easiest thing to do?

How is the front sight fastened in your firearm? Is it pinned or quick change? If it is quick change you can get them from a number of places, I got mine from Dillon. They also have the pinned type and I did install one of those on a M686 6" of mine.

 

[carguychris]

Wow, lotsa responses.

Where to start...

The height of the front sight measures 0.247" above the sight base. It's pinned, so I'm hesitant to change it because I don't really trust myself with a power drill on a gun I paid this much for.

I also don't want to file down the factory sight because, as someone has pointed out, it's non-reversible. I might still get a gold dot or fiber-optic sight someday, but I figure I'll wait until later.

The sight radius of the gun is 7-9/16" (7.44"), measured from the rear sight blade to the center of the front sight. I figured out that the vertical change in POI in inches @ 25yd is equal to the change in height of the rear sight multiplied by 121 (900"/7.44"). The 0.160" sight slide would change it by 1.7", whereas the other rear sight option- a 0.196" sight slide- will change it by 6.1". I think I'll go with the latter.

I don't want to experiment with different holds because I don't usually shoot at silhouettes. I used one the other day because (a) I like to sight-in a gun by shooting at a large target at a range similar to what I typically use for practice, and (b) that's what the range gave me for free when I paid to get in.

I think I'll call S&W and get a price on a 0.196" sight slide, a rebuild kit, and 3 extra springs and plungers.

 

[tomcatt51]

The front sight blades are relatively inexpensive but do require drilling to be installed. Your's is probably the .243. There's a .228 and a .167 also. It's kind of an unusual combination you seem to need.

Were there some of these guns made with a tall front sight base specifically for PPC and the "neck hold"? I know they had the adjustable, multi-position front sight version.

 

[bountyhunter]

Originally posted by carguychris:
Wow, lotsa responses.

Where to start...

The height of the front sight measures 0.247" above the sight base. It's pinned, so I'm hesitant to change it because I don't really trust myself with a power drill on a gun I paid this much for.

I also don't want to file down the factory sight because, as someone has pointed out, it's non-reversible. I might still get a gold dot or fiber-optic sight someday, but I figure I'll wait until later.

The sight radius of the gun is 7-9/16" (7.44"), measured from the rear sight blade to the center of the front sight. I figured out that the vertical change in POI in inches @ 25yd is equal to the change in height of the rear sight multiplied by 121 (900"/7.44"). The 0.160" sight slide would change it by 1.7", whereas the other rear sight option- a 0.196" sight slide- will change it by 6.1". I think I'll go with the latter.

I don't want to experiment with different holds because I don't usually shoot at silhouettes. I used one the other day because (a) I like to sight-in a gun by shooting at a large target at a range similar to what I typically use for practice, and (b) that's what the range gave me for free when I paid to get in.

I think I'll call S&W and get a price on a 0.196" sight slide, a rebuild kit, and 3 extra springs and plungers.

I think you'll end up needing to shave the top of the front sight based on what you said. I had to do that to my M14 and a couple of my 66's so I could get factory ammo to sight in at a reasonable elevation of the rear sight. I think some of the Friday guns they ship just are not sighted in right.

 

[bountyhunter]

Originally posted by tomcatt51:


Were there some of these guns made with a tall front sight base specifically for PPC and the "neck hold"? I know they had the adjustable, multi-position front sight version.

I have actually seen one of those. That would make sense, but it makes no sense to me that SW would ship a gun sighted 18" low with a fixed front sight.