S&W 686 cylinder throats?

[pharmpoke]

My S&W 686 has .356 cylinder throats- is this normal? and after slugging the barrel of this revolver, how do you measure it with the odd numbered rifling? If, for example the bore slugs at .357 the optimal bullet size would normally be .358, but with cylinders this tight what would you do for sizing?

[JW6108]

A caliper type micrometer can be used for an odd number groove measurement. You will need to carefully measure from the corner of one to the (nearly) opposite corner across from it. A little tedious, but it works.

I also have a 686 and have measured the grooves at .356 in it, so I size bullets to .357. They work fine that way. Good luck.

[shooting on a shoestring]

.356 throats sounds like a problem to me. That's tighter than I've heard of a .357 throat before. I think you will want to open those up to a 0.001 larger than your grove diameter. There are reamer kits available. Probably Brownell's would have them. And I'm sure there are several gunsmiths that have them and could do the job.

I'm curious though. Have you shot any cast boolits through it? What were the results?

[MtGun44]

This is covered in the sticky on revolver accy - please review in detail plus use
the search on "cylinder throat" and related topics. There are a great many
excellent posts on this topic out there already. This is very interesting and
can make a substantial difference in revo accy, esp when you have way too tight
cyl throats compared to bbl groove diam. Jacketed bullets are more forgiving
due to being able to grip with only partial rifling engraving (due to being
sized too small by the throats) where lead boolits will either tilt or slip to
reduce accy and are likely to have gas cutting caused leading.

Bill

[mtgrs737]

My 686 had tight cylinder throats too. I sent he cylinder and two others to "The Cylinder Smith" he reamed them to .359" for me. His work is good and he has a fast turnaround time. I have read that Stainless Smith cylinders run to the small side, my experiance bears that out.

www.Cylindersmith.com

[jameslovesjammie]

My 686-5 has 5 cylinders at .357 and one at .3565, according to my elcheapo micrometer. Bore slugs at .356. I haven't had any problems shooting .358 or .357 boolits.

[cajun shooter]

Having been to 3 S&W armorer schools while a law dog that seems to be the standard with the 686. I would send my cylinders to the cylinder smith. The 686 is factory built fot the ugly bullet that has a shiney metal and not the lead that most members shoot. That being said you should be able to shoot 357-358 lead with no problem.

[Snapping Twig]

Sizing to .357 and .358 has worked well for me with my various L frames.

I shoot both the 358156 and the 358429.

[pharmpoke]

thanks crew- I think I'll just load up some of my .358 and see how they do before I try sizing to .357, or any cylinder modifications. Glad it's not just some freak thing with my revolver.