Fixed Sight Question

[PBSmith]

Have a new-to-me fixed sight wheelgun (S&W M10-5) that groups like a match revolver but consistently prints 1-2” left of Point of Aim at 22 yards. Been experimenting with different bullets and loads without success, though much to my surprise, a taper crimp on my favored bullet (Lyman 358432) moves the groups closer to POA than what I achieve with rolled crimps.



Choice of powder does not seem to affect the situation, though I’ve tried only one or two in addition to Bullseye. The three or four bullets I’ve tried so far all shoot to left of the sights.

Problem might be the gun, but it could also be my grip, trigger finger position, shooting stance, choice of lube, seating depth, etc etc. I see no sense in sending the piece off to Smith until I have exhausted simpler and more obvious options, or proven beyond doubt that the problem is with the gun and not me.

Any thoughts on how I might coax groups closer to where I hold - windage-wise? I can live with variance in elevation.

This is my first serious experimentation with a fixed-sight revolver. Maybe I’m expecting too much.

Look forward to your input. Thanks
PBSmith

[Thumbcocker]

You might try adjusting your grip. I bought 2 of the Spanish reimported 10-5's and they are very sensitive to grip and sight picture. If there is not exactly the same amount of light on each side of the front sight groups are way off. FWIW it appears that mine are sighted for 125 ish grain boolits since 150-160 grain boolits shoot about 4" high at 25 yards. Otherwise maybe the barrel could be turned slightly or you can file one side of the sight a bit. You are very close.

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[Outpost75]

Remove cylinder and yoke assembly.

Tighten barrel VERY slightly by striking barrel lug on left side with babbit bar.

If you feel uncomfortable doing this yourself, find somebody who went to S&W armorer's school.

[Larry Gibson]

Remove cylinder and yoke assembly.

Tighten barrel VERY slightly by striking barrel lug on left side with babbit bar.

If you feel uncomfortable doing this yourself, find somebody who went to S&W armorer's school.

I've been doing this for many years though with a slightly different technique. I also use a #2 pencil and draw a line on the frame across the junction with the barrel and onto the barrel. From your target I would turn the barrel in about 1/4 - 1/3 of the scribed line. It's easy to see the amount the barrel is screwed in or out with the line on the barrel turns off set from the line on the frame.

[tazman]

When using that technique to adjust things, does this affect the cylinder gap enough to cause an issue?

[Outpost75]

When using that technique to adjust things, does this affect the cylinder gap enough to cause an issue?

No. You are only tweaking the barrel a degree or two, very minute change.

[Groo]

Groo here
Use a heavy crimp first.
Contrary to common belief , lighter loads require more crimp to insure the bullet does not move before the powder lights off.
[ever see a factory target load WITHOUT a heavy crimp???]....

[PBSmith]

No. You are only tweaking the barrel a degree or two, very minute change.

Minute it is. Using simple proportions, I made a crude calculation to find out how far the front sight would have to move (to the left) in order to bring the group 2" right. If my arithmetic and geometry are correct, that movement is a mere 0.015". This would be easy enough if the front sight were driftable, which of course it isn't.

Rotating the barrel to move the top of the front sight that far to the left requires a rotation of only about 1/4 degree. The operation is going to require much finesse with the babbit bar, even using Larry's trick, which is also useful in drifting open iron sights on rifles.

[PBSmith]

Groo here
Use a heavy crimp first.
Contrary to common belief , lighter loads require more crimp to insure the bullet does not move before the powder lights off.
[ever see a factory target load WITHOUT a heavy crimp???]....

It's worth another set of reloads and trip to the range. As I said in the opener, I was surprised to find that my taper crimp, versus medium roll, made a significant difference in group position. I have no way of knowing which crimp gripped the bullet more tightly, but it will be easy enough to try a firmer crimp in both styles.

Your comment makes me wonder how a no-crimp group will print. I have doubts about getting away with this unless I load one chamber at a time.

[rintinglen]

I've been doing this for many years though with a slightly different technique. I also use a #2 pencil and draw a line on the frame across the junction with the barrel and onto the barrel. From your target I would turn the barrel in about 1/4 - 1/3 of the scribed line. It's easy to see the amount the barrel is screwed in or out with the line on the barrel turns off set from the line on the frame.

This is the route I take. I had at one time a frame wrench which made light work of simple sight adjustments. Typically, all you needed to do was move the barrel just enough to be barely perceptible. I recommend against it on aluminum frames, it is too easy to over do it. But on steel frame guns, it is not a problem. Unless you get really gorilla handed. Then all bets are off.

[Texas by God]

Differences in lighting on the front sight affects my windage sometimes. Try smoking the front sight perhaps.

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[gwpercle]

Adjusting your grip is the easiest thing to try .
Changing grips , different grips , can also effect a change .
Different powders usually move things around ... try more usually you will find shifts in impact with different powders and charges .
Sometimes primers can do it .
And of course different boolits will move things around .

There is no formula , you just have to keep experimenting with things until you find the right combination .
I have gone through all of this with the fixed sighted Model 58 S&W 41 magnum in my avatar !
I have found about 4 loads that print right on . The Ahrend's Grips helped a lot .
It just takes some time and experimentation .... but that's why we do what we do .
I never thought to try changing the crimp....that made a bigger difference than I thought possible in your group , good one . Primers will do it too ...sometimes .
Keep experimenting you will find the right load(s).
Gary

[Wayne Dobbs]

I have one of the reimported 10-5s that shoots 5" right at 25 yards with Outpost's DEWC and 3.5 Bullseye load. Great groups, but nowhere close to POA. My calculations show that I need about 0.033" of sight change to fix that.

[Petrol & Powder]

All the above is good advice.

You're pretty close and the group is good. If that group remains consistently to the left, then slightly twisting the barrel in the frame is the way to "adjust" the fixed sights. I have not heard of Larry's pencil line trick before but that's excellent method. That one is going into the permanent filing cabinet of tricks.

One of the great things about fixed sights is once you get them where you want them - they pretty much stay there.

[SSGOldfart]

You might want to try loading a different boolit,first and run it a little faster then target loads if that doesn't fix your problem then have the barrel turned
You can test your grip ideal by changing distances to the target before jumping into turning barrels,or adjusting the load.

[alfadan]

I would try more finger through the trigger. I have to remember quite a few different "kentucky windages" for my fixed sight guns!

[ABJ]

I would try more finger through the trigger. I have to remember quite a few different "kentucky windages" for my fixed sight guns!

I helped my better half with her baby glock the opposite of above quote. She would put the right side of trigger on her first joint and push all her shots to the left. Just trying different things I had pull her trigger finger out not quite to the whorl and shots centered up.
I have noticed every shooter's grip can be different so you have to play around with it a little. Handgun accuracy and point of impact is highly affected by grip placement and trigger finger.
I am spoiled being a Bullseye shooter and having tuned hardware so when I pick up a revolver that is box/stock factory even I have to reeducate myself to make it shoot where I want.
Tony

[JoeJames]

I would try more finger through the trigger. I have to remember quite a few different "kentucky windages" for my fixed sight guns!

I have really noticed that effect with fixed sight 32 S&W hand ejectors. I think part of the reason is they are so much lighter than a K frame, that finger placement on the trigger becomes more important. Of course the right grip on the revolver makes a difference also.

[alfadan]

I have really noticed that effect with fixed sight 32 S&W hand ejectors. I think part of the reason is they are so much lighter than a K frame, that finger placement on the trigger becomes more important. Of course the right grip on the revolver makes a difference also.

Dad taught me to squeeze the trigger, then once fired (or dry fired) to keep squeezing and watch the front sight to see which way it moves. Easier on the 1911 since its single action. If it goes left you have not enough finger through. If right, then too much finger thereby pulling the gun right.

[JoeJames]

Dad taught me to squeeze the trigger, then once fired (or dry fired) to keep squeezing and watch the front sight to see which way it moves. Easier on the 1911 since its single action. If it goes left you have not enough finger through. If right, then too much finger thereby pulling the gun right.

Well put. Said it better than I could. About half the time, I forget to mind that very point. But as I said, I don't think it is as much of an issue with say an N frame as it is with an I frame.