Burn marks

[peterk1234]

Hi Everyone,

Is this a common mark on the cylinder? I also attached a pic of what I believe is the culprit, the screw (and hole) for the front sight. The marks really do not want to come off when cleaning.




Pete

 

[OldChief]

You can cut this down some by shooting nothing with less than a 158 grain projectile.

 

[ridgewalker]

Yeah totally normal and you are correct regarding the source. I don't mind or notice the burn marks on the front of the cylinder but the ones you highlighted bother me. I don't want to be too aggressive removing them especially from my matte finish guns because I don't like a polished look. The standard S&W revolver finish is easier to clean these marks off.
I have heard of people putting in longer screws to minimize that effect . I hope someone can supply the details of size and source.

 

[Collo Rosso]

The usual state of my 627, dirty. I shoot the snot out of this thing and get those marks all the time. Not sure why OldChief says don't shoot anything less than 158 grain will help. All this gun has seen is 158gr. plated RNFP's or coated SWC's.
I don't worry about it. When I clean it I cut a small piece from a lead removal cloth and start rubbing. Takes care of those marks and the powder burns on the cylinder face. If your shooting lead that same piece on a jag works great down the barrel. So far it hasn't polished the bead blasted finish.
Should it start to polish the finish I'm still not going to worry about it. Like I tell my son, I'm doing my best so someday you inherit a pile of worn out guns.

 

[TNZ71]

I just noticed those on my M66. It had me stumped. Thanks for the education.

 

[cold blue steel]

They are pretty notorious on newer 586's too

 

[robert1804]

A gentle scrubbing with some CLP or other solvent with a copper brush will get those scotch marks off that kind of finish easily with no harm to the surface.

 

[iPac]

You are correct, it is the front screw hole for the sight. Just be thankful your gun is STS and not blued.

The reason this happens is because the screw hole is drilled completely through the top strap but the screw only fills it so far leaving a hole with some depth to it. When you shoot ANY cartridge, doesn't matter what load, the hot gases escaping from the b/c gap rush out. Consequently those gases push up into that hole with no where to go but directly back down acting like a tiny torch at that exact spot. Hence the perfect little marks. Just watch so it doesn't start to 'pit'.

The first Python I bought was from an old family friend who bought it for hunting. He had the old time original Bushnell magnum phantom scope and mount installed which required the top strap be drilled and tapped for the 2nd hole needed to mount. That hole was directly over the b/c gap. Besides the top strap being drilled, this gun was all of 98% condition bluing and he didn't shoot it that much at all. I immediately removed the scope and mount, reinstalled the original open sight and installed a domed stop screw to plug the hole. After repeated shooting I started noticing perfect circle 'dots' on the cylinder. A little bit of critical thinking exposed the issue. Sadly, I had already shot the gun enough that one or two of those holes actually breeched the bluing and the rest are noticeable discoloration. There is nothing I can do about it now. What I did do though was remove the stop screw to allow the gas to vent up and out. Don't really care for the open hole but it is better than cylinder scarring.

I also installed the B square rib clamp scope mounts and bought a better scope to use for my hunting purposes. With that open hole the hot gases still reach a half inch above the back strap and burnt the anodized finish off the base of my new scope.

That hot gas is nothing to mess with and S&W should have expected this to happen. The solution would be to get a screw that will completely fill the hole in leaving no where for the gas to enter so it channels away and doesn't get directed at one tiny spot.

 

[cold blue steel]

Is there any chance at all of finding a screw to fit that spot? In my case and many with the newer blue 586's this can be a nasty little mar!

 

[9mmsubgun-m11]

I use BreakFree CLP on mine and it wipes away pretty easy.

 

[BLUEDOT37]

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

I have heard of people putting in longer screws to minimize that effect . I hope someone can supply the details of size and source.

This is the one I bought. Originally it was stated the 6-48 x 3/16" screw would work but I found it too short & ordered the 1/4" long screw instead.

Note: The beveled head is a little thicker that the factory's so it does not screw down flush. If that's a problem for you, don't buy it.

Also, a 7/32" screw would probably be best but I didn't see one, so the tip of the 1/4" long screw needs to be filed flush as it protrudes a tad into the frame window. You'll likely still see a very small burn mark there but it'll be greatly reduced.

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

.

 

[peterk1234]

Thanks for the replies. Time to find a longer screw. Pete

 

[robert1804]

This is the one I bought. Originally it was stated the 6-48 x 3/16" screw would work but I found it too short & ordered the 1/4" long screw instead.

Note: The beveled head is a little thicker that the factory's so it does not screw down flush. If that's a problem for you, don't buy it.

Also, a 7/32" screw would probably be best but I didn't see one, so the tip of the 1/4" long screw needs to be filed flush as it protrudes a tad into the frame window. You'll likely still see a very small burn mark there but it'll be greatly reduced.

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

.

These are the screws I use also. They come in a bag of 10. Their degree of bevel matches the bevel of the sight. I've put them in all my blued guns and most of my stainless. In a 586 Classic, I tried filing a slighty rounded shape and letting it protrude a few thousandths. The screw then acts as a diffuser and distributetes the hot gasses more evenly.

 

[Nemo288]

Cool idea.
While I am pretty good with metalworking my fingers are getting old and arthritic.
Not sure I have the skill to work something that small anymore.
I have found that 1500 and then 2500 grit wet/dry sand paper leaves a nice mirror finish on metal.

 

[savit260]

My 627 does that, and it cleans right up with Ballistol.

 

[markeb]

Here's what I use, ever so gently.