Rear site screw?

[BigBill]

I seen a video on yt were the rear sight screw isn’t long enough and causes a vortex that marks the side of the cylinder. Is a longer screw available to avoid this problem?

I as because I have a new 29-10.

 

[BLUEDOT37]

Forster Slotted Oval .200" Diameter Head Screws 6-48 Blue

Yes, with a caveat.

Midway sells a screw that's close. The head of the screw has the right shape & taper but it's a tad thicker so it sticks up a bit.

They had a 3/16" long screw but it is too short & 1/4" is a little too long so 7/32" would be about right, but I don't see one.

I used a 1/4" on one of my revolvers, that I filed it's threaded end flush to the inside of the frame.

It's better but you still get a little of the blast mark from the screw hole on the cylinder.

If you don't mind the height difference it's worth a try.

Just keep the old screw when you want that "fitted" look.

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MidwayUSA link:
Forster Slotted Oval .200 Diameter Head Screws 6-48 x 1/4 Blue Pack of 10

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N-frame models with a long barrel breech extension, like the 45ACP revolvers, don't have that problem because the B-C gap is farther away from the screw hole. Most of the magnums are right by it.

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[BigBill]

Thank you bluedot37 I figured someone would know here.

I’d like to fit the screw properly before I shoot it.

What did we do before the internet it’s a information highway we have a wealth of info at our finger tips. Anything we don’t know about either search it or find the correct forum and ask.

I have the experience for 55 years in mechanics and how things work from designs to real world applications. Anything my son doesn’t know he searches the internet, it’s a great tool.

 

[BigBill]

These screws 6-48 x 1/4” can be found on eBay too. You need to make them .187” long to fill the hole flush so there’s no vortex.

 

[targetman]

Hello, just call Smith & Wesson Customer Service. They know about the problem with the short sight screw. Explain what's going on and they will ship you the correct length rear sight screw free of charge. I called in February for a Model 629-6 and had the correct screw in 2 weeks time.

 

[Patrick L]

What exactly is this?? I've not heard of it. Am I correct in assuming that somehow the recess caused by a too short sight retaining screw somehow traps blast caused by firing, and somehow blemishes the cylinder????

Is it a finish blemish, or does it actually go into the steel?

Again, this is a new one for me.

 

[targetman]

Hello, for my case of shooting 240 gr Hi-Tek coated lead bullets, it was leaving powder burn marks and lead residue at the end of the cylinder between the cylinder flutes. Unsightly after about 150 rounds fired but wipes away easily with a lead-away cloth on my S&W 629-6. I haven't seen any etching of the cylinder yet but I've only had the 44 Mag a few months with about 700 rounds through it.

 

[dondailey]

I have a 629-6 with this exact problem and just found this thread. I think eventually it would be pitting the cylinder. I emailed s&w, requested a new screw, they answered quickly saying they would be mailing it to me. Ask and you shall receive. This is the third time I have asked s&w for service and each time they came through.

 

[Hurryin' Hoosier]

Durned if I know what this is all about.

 

[ruggyh]

I have a number of 460 S&W and 500 S&W with "short screw", and yes they get the vortex residue as described.
There have been a number of thread where owners proclaim the cylinder is hitting the top strap.
I have put thousands of rounds through these guns and no have any pitting as a result, the marks clean of - if I don't have get any damage surely the lower pressure cartridges aren't going to get any damage either. No difference than cleaning your cylinder face.

 

[dondailey]

I have a number of 460 S&W and 500 S&W with "short screw", and yes they get the vortex residue as described.
There have been a number of thread where owners proclaim the cylinder is hitting the top strap.
I have put thousands of rounds through these guns and no have any pitting as a result, the marks clean of - if I don't have get any damage surely the lower pressure cartridges aren't going to get any damage either. No difference than cleaning your cylinder face.

I agree it is not a huge problem on a stainless gun. My marks came off with a tiny dab of mother’s polish. It bothered me just enough to ask for a better screw. If it were on a blued gun, it would be a problem.

 

[Hurryin' Hoosier]

What exactly is this?? I've not heard of it. Am I correct in assuming that somehow the recess caused by a too short sight retaining screw somehow traps blast caused by firing, and somehow blemishes the cylinder????

Is it a finish blemish, or does it actually go into the steel?

Again, this is a new one for me.

I'm lost too, brother. No idea what this is all about.

 

[dondailey]

What exactly is this?? I've not heard of it. Am I correct in assuming that somehow the recess caused by a too short sight retaining screw somehow traps blast caused by firing, and somehow blemishes the cylinder????

Is it a finish blemish, or does it actually go into the steel?

Again, this is a new one for me.

I wish I had taken a photo before I cleaned it. Apparently there is a vortex or redirection on gases that reflect from the screw hole. It marks the cylinder directly below the screw hole. Mine were concentrated circles with a dot in the middle. Perhaps it would cause pitting over time, but as another commenter said he didn’t have pitting with higher pressure cartridges even after many rounds. On stainless guns, this is mostly just an annoyance.

 

[ruggyh]

What exactly is this?? I've not heard of it. Am I correct in assuming that somehow the recess caused by a too short sight retaining screw somehow traps blast caused by firing, and somehow blemishes the cylinder????

Is it a finish blemish, or does it actually go into the steel?...

It does not blemish the cylinder, it is simply powder residue that is reflected back onto the the top of the cylinder as a result of the low pressure area caused by the depth of the hole. (Same residue that dirties the cylinder face).

The residue pattern is a function of the pressure , powder and hole depth, it does vary some between guns.

I have a attached a photo.

Easily removed from stainless gun with leadaway cloth or traditional cleaning methods.

Blue guns don't show the residue to the extent stainless guns do and you should use appropriate cleaning method to remove.