L Frame M stamp

[pantannojack]

Considering the necessity to send early L frames to the Mother Ship for modification or risk hammer nose bushing failure, I wonder why this issue has never appeared in K Frame magnums? I had a 586 no dash fail decades ago and lately have seen a 686 no dash with the M stamp. While examining the nose bushing it seemed very slightly recessed. That may be why it is for sale as I had a 65 RB with a recessed bushing which caused cylinder rotation resistance when firing magnum loads. Any wisdom?

 

[Borderboss]

Considering the necessity to send early L frames to the Mother Ship for modification or risk hammer nose bushing failure, I wonder why this issue has never appeared in K Frame magnums? I had a 586 no dash fail decades ago and lately have seen a 686 no dash with the M stamp. While examining the nose bushing it seemed very slightly recessed. That may be why it is for sale as I had a 65 RB with a recessed bushing which caused cylinder rotation resistance when firing magnum loads. Any wisdom?

I'm no gunsmith, but that bushing looks like some "bubba" gunsmithing. What's with the elongated firing pin hole?

 

[Protocall_Design]

When the firing pin bushing is set back like that, you will have problems with the primers backing out and locking up the action. The FP bushing on hammer nose guns like that one need to be flush with the rest of the recoil shield. The hole for the firing pin is obviously way oversized, too. That bushing needs to be replaced.

On the newer, firing pin in frame guns, the FP bushing has a slight crown to it to make sure the primer doesn't back out.

 

[Hondo44]

What Protocall_design posted.

Because the primer almost always backs out upon ignition*, especially on reloaded cases. But it's soon followed by the case which slams the primer all the way back into its pocket when the bushing is flush.

However, with a recessed bushing the primer will not be completely re-seated in its pocket because the case head with its much larger diameter can only slam back against the recoil shield and not reach the bushing if it's recessed.

Therefore the primer is not fully re-seated and it will hangup on the edge of the bushing socket. This binds up the cyl for the next shot.

*To observe this, load an empty case with just a live primer, then shoot it in your gun. The cyl will bind and have to be rotated with your fingers. The reason is that there is no powder charge in the case or bullet resistance to the pressure, to slam the case back and re-seat the primer!

 

[Nightowl]

Whoever replaced the bushing should have sent it right to the factory after the install. Most bushings fit flush or slightly raised and then filed flat with the frame. Those that were recessed were to be sent back to the factory before issue.

 

[Lowa]

That's damaged. Not being stamped, but being messed up isn't a good thing. Definitely send it back

 

[Hondo44]

Considering the necessity to send early L frames to the Mother Ship for modification or risk hammer nose bushing failure, I wonder why this issue has never appeared in K Frame magnums?

To my knowledge, in the K frame assembly process the bushings were correctly assembled and flush. The problem appears to have developed on the new L frame assembly process. Perhaps the crimping ring you see in the photos was done with excess force. Or the bushings were slightly undersized.

 

[pantannojack]

Thanks Hondo, for the explanation. The 586 no dash I returned in the 90's had broken the frame seat for the bushing and they replaced the frame using my other parts. The pic in my original post is from a 66 RB I had to turn down because S&W refused over the phone to fix it saying they had no parts. My original question should have asked why the K frames were not notorious for failure when the L frames were if this is such a weak point.

 

[Nightowl]

It was not exactly a weakness. The L frame hammer nose and firing pin bushing were large enough that with some very hot ammunition, notably the 125 grain bullets, the primer would flow back into the bushing hole and tie up the cylinder. This occurred on a very few guns, but enough that Smith redesigned the bushing and hammer nose into a smaller diameter and replaced all them on their dime. Many of the early guns went to law enforcement, so guns locking up were critical. Parts kits and instructions were sent to armorers in agencies to replace the specific parts and stamp them with an M to indicate the update. Tjey also sent ammunition to test fire all the updated guns before returning them to service. L frames marked with the -2 already had the update from the factory and were not marked with the M.

 

[MP-5]

This is not to say all "non-M" stamped L frames locked up. I have a 686 no-dash 6" that I have used for hunting. I have developed some hot hunting loads with a variety of bullet weights and Federal primers. I also used factory Federal 125 grain and 110 stuff which was known to lock up those L frames. Trying to lock this gun up, I couldn't. Most all of my other L frames are M stamped and also work perfectly. In the used market I would not shy away from a "non M" stamped L frame. I have an Australian AFP 681 no dash that I believe has the M stamp, although it has so much stamped in that frame I'm not sure what they all stand for. That Aussie 681 runs with everything you stuff into it.

 

[Hondo44]

As I recall, the M is stamped on the cyl face.

 

[Grayfox]

The gun in that picture definitely needs to be fixed.

I have an early 586 no dash that has never given me any problem. If it ain't broke, don't fix it.

 

[Catwrangler]

The gun in that picture definitely needs to be fixed.

I have an early 586 no dash that has never given me any problem. If it ain't broke, don't fix it.

I too have 586 purchased in early 83 NIB. Prolly 8000 rounds of 125-180 grn.- FactoryAnd some hot handloads. Bushing face and FP hole look great. Although it's from the Punta Gorda era, bluing, fit and fitting& polishing are beautiful. Patridge front sight. I shot hunters silhouette for about two years. A real tack driver on those 75yd. Turkeys and 100 yd. Rams. It's not going anywhere. I fear that my son in L.A. will figure It's too big a hassle to get back to CA. AND get raped selling to a dealer. Sad thing is he loves shooting and when he visits, he outshoots me with my glock 17. He hates the hassle of Ca. as a whole, but the $$$ he makes as a graphic designer at IMAX keeps him rooted to the
Shakey Side

 

[S&W Fan]

The M stamp is done on the frame above the model number, no mark on the cylinder. This is my late father's 1981 no dash I inherited in 1992, he bought it new in Sept. 1981. He sent it in as it was binding with various magnum ammo.

I had a no dash 586 without the M I recently sold that never exhibited any binding with the few magnum rounds I fired through it.

 

[Hondo44]

Yes, for that modification, the M was stamped in the yoke cut and is known as a 686-M.

The M on the cyl was to denote the change to the left hand threads on the extractor rod for a short time after the change.

 

[S&W Fan]

I'll amend my info on my no dash 686. My dad took it back to the shop where he bought it-now long out of business but it was the "big" shop in Tucson at the time, Jensen's Custom Ammunition on Pima St. The shop sent it back to the factory, when it returned it had the M stamp and in the 40 years since with unknown number of magnum rounds through it there hasn't been a single issue. Used it to teach both my sons to shoot a handgun.

It will stay in the family for at least two more generations. It's all semantics but I'll keep calling it a no dash with the M stamp as it went back for the work/stamp , have the original box too, that didn't go back with the gun for the work, all good on my end.

 

[quikdraw67]

I'll amend my info on my no dash 686. My dad took it back to the shop where he bought it-now long out of business but it was the "big" shop in Tucson at the time, Jensen's Custom Ammunition on Pima St. The shop sent it back to the factory, when it returned it had the M stamp and in the 40 years since with unknown number of magnum rounds through it there hasn't been a single issue. Used it to teach both my sons to shoot a handgun.

It will stay in the family for at least two more generations. It's all semantics but I'll keep calling it a no dash with the M stamp as it went back for the work/stamp , have the original box too, that didn't go back with the gun for the work, all good on my end.

Nice. 2 piece box with the hand written label.
A keeper for sure.

 

[Mike SC Hunter]

I have a nickel 4 in no-. that I bought when they first came out. It has never missed a lick with magnum loads. I don't particularly "cotton" to it and anything with USELESS weight adding full lug. I haven't shot it in about 5 years. It's part of the pile so it's not for sale. The only 2 "L's" that I do like is my 696 and 686 mtn gun.