Those of you who shoot older K/L frames, which spare parts do you keep on hand?

Understandably the hammer mounted firing pin is one, is there anything else critical?

Thanks

Bullets

I think the problem you may find is that parts probably aren't interchangeable, but selective fit.

Most parts would be fitted by a gunsmith. An oversized hand.     ( what turns the cylinder) and the firing pin would be the parts you might want. Even double action revolvers out of timing will work single action.
Most revolvers don’t get thousands of rounds through them.

hand

cylinder stop

firing pin

springs

hand

cylinder stop

firing pin

springs

I have SW’s made in the early 50’s that are chugging along just fine. Reality is you will destroy your ammo budget or reloading equipment before you induce enough wear or damage to a S&W revolver to need parts or service. And as mentioned to fit parts right you need a gunsmith who knows what they are doing with a revolver and those are few and far between.

I have been running S&W revolvers for 40+ years and have never needed a spare part or to service  them aside from routine cleaning. One of my K frames ( model 17-3 ) has seen in excess of 100 thousand rounds with no attention beyond cleaning just keep shooting.

Have been running Smiths for better than fifty years.  My oldest dates to 1905.   I’ve never replaced anything.  Nada.

There is nothing that wears out from shooting on a S&W K or L frame that can be fixed by simply changing parts and no extra work. I have never heard of a hammer mounted firing pin breaking. I'm sure it can happen, but so can anything. I'm sure there are examples out there with 100,000 rounds, and 1,000,000 dry fires on them with the original firing pin.

If you want to shoot them competitively, all you can do is shoot them until they don't, then take them to a gunsmith. Some work you can do yourself, such as shimming the cylinder, but you aren't going to be setting back a barrel unless you are already a gunsmith. Fitting a new hand isn't super easy either.

The hammer nose (firing pin really) and rivet.
Main springs and it doesn't hurt to have a couple of mainspring tention screws.
Save the old filed on one's too.
Some unbuggered side plate screws are nice to have.

This way if you do get an older gun for a good deal you can have it going quicker.

I used to keep Privi Part 38 special around because it had hard primers.
Then I could see if a new acquisition needed help.

Good to know, thanks for the input. In that case saves me some hunting down parts.

I fire mass quantities of ammo thru K and L  frames.  I own over 40. Just about all of them former police guns. .38 Special is far and away the main ammo I reload. I don't keep individual round counts, but for some of the models, it's a LOT.  Esp a 6" mdl 19. I hunt pigs and shoot pistol shilouette with it.

I have replaced exactly four parts not counting screws etc I dropped on the shop floor and never found again.  

A hand, a crane, an ejector rod and a firing spring strain screw.  

The hand, rod and crane were on a mdl 14 that some idiot liked to spin and flip the cylinder closed, All were bent.  

The strain screw was replaced because another idiot thought taking a file to the thing would help the trigger pull.

I'd stock a hand, firing pin assembly and a full set of springs and call it good.

It's going to depend on how YOU use the gun.
Other people, who use the gun differently, will have drastically different wear patterns.

Let's say YOU live and die by the Bill Drill or any thousands of other high speed shooting events. Your patterns of wear/failure/replacement parts will differ greatly from shooter #2 who only fires his gun for fun at the range, no real speed involved.
Add shooter #3 who fires very heavy handloads, single action only at deliberate pace.
#4 shoots a hunting handgun.

Skip ahead several years and you'll have:

No parts needed.
Gun got excessive endplay after X number of years.
Gun needed "this" to cycle reliably (fast).

Overall modern revo's are pretty solid but you (and your use) can and will wear some parts much faster than another user. It's like a car, you practice launching fast from a stop,,, you'll need a clutch much faster than a guy who just likes to cruise at 95mph + on the freeway.

Expect some wear replacement (unless your use is light), there are people who'll fix what's needed, videos will make some of those fixes easy for a mechanically inclined individual. It's not a "universal" expectation it's use specific.

L-frames endure in my experience much, much longer than K-frames, but if  K-frame meets your need? Just do the maintenance as wear occurs and be happy. All mechanical devices require maintenance at some point.
If car owners were like some shooters, their ride would last forever, others will need some stuff done from time to time

ETA: maintenance in a revo isn't a sign of abuse, it's a sign of heavy use in one form or another.

I have had it happen to me.  The gun was used, so I have no idea how many rounds or if it had been dry fired a lot.  The hand was also worn, so it had seen a lot of use, whether fired or dry fired.  Probably a lot of dry firing would be my guess, as it was a model 58.
I managed to fix it, whole new hammer and new hand.  Shoots fine now.

The one problem with parts is the hand. I went through the armorers school in1979 and I could call S&W and order hands by the width. New gun hands fan.089 to.092. I have been picking up K and N frame hands were I can but supply is limited.
Ron Powers has a hand.099 but if you wear the ratchets using the .099 you will need to replace extractor and start over.

After about 50k rounds through my m66-8 it needed a new cylinder stop/spring and cylinder.

I've had to replace the gas ring on my m19-3 twice