I have a chance to buy a nickel 586 no dash, DOB about 1984. It is not M stamped, so has not been to the factory for modification. What exactly is the modification done by the factory to the no dash and dash one guns? Is it OK to keep in the original condition, or should I send it back to S&W for modification? Will it affect the value if modified?

The modification "M" is replacement of firing pin and the bushing it passes through on the frame.

Non modified pistols MAY experience primer flowback into this area, locking up the pistol when shooting hot 125 grain ammunition.

I am not aware of a difference in value with or without the modification.

I just bought a 586 no dash M and back when the problem was discovered I had one that I sent back for modification.

Some people avoid shooting 125 grain rounds and some never experience this issue in spite of shooting 125g rounds - it wasn't every pistol that locked up, but being pistols need to be reliable, all of them qualified for the modification.

I have a no dash that doesn't have the M and it doesn't bother me or my shooting.

Thanks for the info. I'll shoot it when I get it and see if there are any problems. I suppose I could load with CCI primers or small rifle primers if flow back is a problem.
Clay

The design of the 586,as were all of the centerfire S&W revolvers, the same, i.e. hammer nose mounted firing pin and bushing. I do not recall this issue coming up with the model 27 nor the Combat Magnums, model 13 etc. What changed when they manufactured the 586/686 that caused this issue? Anyone care to hazard a guess?
regards,
Ralph

Have a Look at this Old Post It gave me the answer..
Gunhacker's Post
Recall, 586 S&W?

Thanks Gary, that's a good thread. Ralph has a good question though. Why was primer flow not a problem on earlier 357 mag revolvers?
Jim

BTT, the question still stands. Why would the same firing pin/bushing combination be marginal in a L frame and OK in a J/K/M frame? Were the old original pin and bushing changed for the L frame? That doesn't make sense.

Fom the S&W recall notice:
"Do not return L-frame hammer-nose bushings from your spare parts inventory inasmuch as they are useable in J, N and K-frame revolvers, which are not included in this Product Warning."

I compared my new 586 unmodified to a 686 M this weekend. It appears the firing pin on the 586 is larger diameter and protrudes further past the bushing than the 686 M firing pin. The bushing on the 586 also has a larger diamenter hole to accept the larger firing pin. The radial gap between the firing pin and bushing hole is equally close on both models.

Here's a copy of the original letter published by S&W regarding these modifications. I recently bought a LNIB 686 that had not been modified. I called S&W and inquired about it. They sent me authorization for return and repair and after a month the gun was returned with the new parts installed and an "M" inscribed on the frame. Excellent customer service from S&W. As a sidenote, I have a friend who has an unmodified 586 and he has put over 10,000 rounds through it since it was new with no problem. Instances of lock-ups in un-modified guns was very rare.



"SMITH & WESSON
MODEL 581, 586, 681, 686, or 581-1,
586-1, 681-1, 686-1 & 686CS-1, REVOLVERS

RECALL: Reports have been received from the field where the combination of a SMITH & WESSON L-FRAME 357 MAGNUM REVOLVER and some .357 Magnum ammunition has resulted in unacceptable cylinder binding. L-frame revolvers bearing model numbers:

581, 586, 681, 686, or 581-1, 586-1,
681-1, 686-1, 686CS-1

Cylinder binding can cause a failure to fire. Mishandling a revolver while freeing the cylinder can result in accidental discharge.

Cylinder binding can result from a number of causes, including characteristics of an individual revolver or the use of ammunition, which does not conform to industry pressure specifications or is particularly fast burning. Recent developments in ammunition manufacture emphasize the production of .357 Magnum ammunition with increased velocity and greater primer sensitivity.

Although there have been very few reported incidents of cylinder binding, in view of our concern for our customer's safety and the reliability of Smith & Wesson products in all circumstances, we issue the following warning:

In a situation where a failure to fire can be critical - such as law enforcement or personal protection - do not use .357 Magnum ammunition with an L-frame revolver bearing model numbers 581, 586, 681, 686 or 581-1, 586-1, 681-1, 686-1, 686CS-1 without an "M" over the model number until you have had the revolver modified.

Those who need to use their L-frame revolver under these conditions prior to modification can safely fire .38 Special caliber ammunition.

Smith & Wesson has developed a modification to improve existing L-frame revolvers. This improvement enables them to fire all .357 Magnum ammunition, without cylinder binding. Shipments of L-frame revolvers from our factory after August 21, 1987 already include this improvement.

You can check if your revolver includes this improvement by looking at the left side of the frame when the cylinder is fully open. If your revolver has been stamped either with a "2" or higher number after the basic three-digit model number or with an "M" above the model number, your revolver includes this improvement and does not need modification. If your revolver bears the model number 581, 586, 681, 686, or 581-1, 586-1, 681-1, 686-1, 686CS-1 without an "M" over the model number, it does not include this improvement and your should have your revolver modified.

Smith & Wesson will modify your L-frame revolver free of charge to eliminate the possibility of cylinder binding with .357 Magnum ammunition. Law enforcement agencies wishing to arrange for modification of L-frame revolvers should call 800-458-8469 between 9 A.M. and 6 P.M. Eastern time (MA residents call 413-734-8244). Other users should send their revolvers to a Smith & Wesson Warranty Service Center, specifying "L-frame improvement program" and enclosing their name and return address.

One of the modifications to improve the L-frame revolver is the installation of a new hammer nose. This obsoletes all old L-frame hammer noses (part numbers 4702 and 7513) and all old L-frame hammer assemblies (part numbers 3366, 3378, 3380, 3382, 3391, 4722, 4723, 4726 and 4728) in field parts inventories. Superseded parts should never be fitted into a modified revolver as this may result in malfunction. It is essential for safety that you return these obsolete L-frame hammer noses and obsolete L-frame hammer assemblies for a free exchange to:

Smith & Wesson
Service Department
2100 Roosevelt Avenue
Springfield, MA 01101

Do not return L-frame hammer-nose bushings from your spare parts inventory inasmuch as they are useable in J, N and K-frame revolvers, which are not included in this Product Warning.

We regret any inconvenience this may cause. Smith & Wesson's first concern is the safety of its products and the protection of its customers.

This post in the Ammunition forum details trouble Texas DPS had with misfires and primer setbacks with their M28s. Might be relevant to the 586?

http://smith-wessonforum.com/eve/forums/a/tpc/f/6951070...181057913#8181057913