S&W Porting problem?

[broomhandle]

Hi Guys,

I need some help here.:confused:

I have a S&W 686 six inch revolver it has the single port in front of the sight.

I have discovered that with a medium cast bullet load that is very accurate in my S&W 4 inch 586.
The groups with the 686 are larger by 1/4 . :( (from a rest)
No leading in barrel force cone and rifling at all

I did clean the port after I shot it tonight.
The port did have some lead build up in the top cut and right side of the barrel port cut.
I scraped all of it off.

Do you think this was the reason for the larger groups?

How often should I clean the port and what is the best way to do it?

Thanks for you help,
broomhandle

[HCL]

I have a 629, 6 1/2" barrel, single port in front of sight, I too have noticed some lead deposits inside of porting, and on front/port side of front sight but have not noticed anything else, (shooting bad). Other than having to clean the lead off, the port does not seam to affect accuracy that I have found at all. Very accurate pistol! I usally clean the lead off with a tooth brush, if needed a bronze bore brush with oil and light scrubbing.
Have you slugged both pistols, are they the same size, barrel and cylinder? If one is differant than the other, that could be your issue?? The cast/sized dia of the boolit may have to be adjusted for one of the guns?
I am guessing?? Hopefully someone will have a educated answer for you.
Mike

[Lloyd Smale]

every gun is different and you cant expect a load that shoots one inch in one gun to shoot one inch in the next. I doubt the porting had anything to do with it.

[Bass Ackward]

I have discovered that with a medium cast bullet load that is very accurate in my S&W 4 inch 586.
The groups with the 686 are larger by 1/4 . :( (from a rest)
No leading in barrel force cone and rifling at all

broomhandle


BH,

Are those two guns made close enough to the same to compare anything? You would have to compare multiple loads before and then port the same gun and test again.

I only ever ported one gun, a 44Mag back in the early 70s when it was all the rage. Before and after testing actually showed mixed results with some loads doing better before and some after.

So based on the statistics for one gun, I call it a draw.

[broomhandle]

Hi Fellows,

I mentioned, that I cleaned the port and removed all the build up I could.

I picked at the main chunk with a dentist pick. Then after that came out, I used some small brass pins I had, to remove the crust at the corner of the barrel port and the crown.

Tried it the next day. It shot a much tighter group, as good or tighter than the other pistol.:-D

My guess, the small amount of lead build-up was enough to affect the crown and alter the group size.
I will clean it more often in future.

Thanks for your replys, you guys have helped me many times in the past,:drinks:

broomhandle