Cylinder length on the S&W 686?

[neven]

Could someone with access to a Smith & Wesson 686 revolver please measure the legth of their cylinder?

Has this length changed over the years with the different dash-something model numbers?

Thank you,

Neven

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[Velzey]

1.620 that's on a no dash. I don't think the overall length has changed over the years.

 

[neven]

Thank you Valzey.

Adding at least 0.06 inches for the rim thickness, this means that the max C.O.L. for any 686 is at least 1.620 + 0.060 = 1.680'' or around 5.6% higher than the standard 357 mag COL of 1.590'' (5.6% more energy with the same max pressure if loaded to use the full cylinder).

I would appreciate it if someone could make the same measurement on the Ruger GP-100.

 

[neven]

My estimate for the extra energy based on a quick calculation of extra powder volume above was much too conservative. Here is a more accurate calculation based on the reported 686 cylinder length of 1.620'' and my calculated max COL of 1.680'', in case someone else may be interested.

- 180 grain hard cast lead bullet 0.75'' long,
- a standard length 357 cartridge 1.59'' long leaves
1.59'' - 0.75'' - 0.06'' =0.78'' for the powder.


S&W 686 MAX COL = 1.68''
this is 1.68''-1.59''= 0.09'' longer than 1.59''
leaving an extra 0.09'' for the powder.

The relative increase of available volume for the powder
delta_V/V = 0.09/0.78 = 11.5%

This is a significant increase in available volume.
For example, 13.5 grains MAX of Hodgdon H110 becomes
13.5 * 1.115 = 15 grains MAX with the same powder density = same max pressure.

 

[2gr8dgs]

1.607 on my 4" gp100.
1.622 on my 5" 686+, a dash 6.

 

[Rudedog]

Very interesting. I will be reloading for my 686-4 soon. I have 2 boxes of 190 grain lead flat tips that have been on the shelves for too long.

 

[OldBroad44]

686-4. 4.05 cm. Or 1.59 inches. Just measured roughly with ruler, not calipers.

 

[neven]

Thanks to everyone that replied.
If I come across any more cylinder lengths,
I will post them here in a table.