I'm thinking my next handgun may have to be a 357 and the 19 has some beautiful lines.  Two things I wonder though; what frame 'letter' is the 19, and is this the gun that I've heard described as a 38 that can shoot 357?  ie:  you can but it's not really up to the challenge?  

The Trooper is also interesting, though it lacks the beauty of the 19 to my eye.  What is the difference between a mark 3 and mark 5?  

If you've shot both, which of them impresses you more?  Which is a better built gun?  Lots of opinions here I'm sure!  

Thanks for looking!

The S&W Model 19 is a "K" frame.
S&W's frame sizes ran from the small "J" frame to the mid-sized "K" frame, to the "in between" "L" frame, to the large "N" frame.

Famous writer and Border Patrolman Bill Jordan talked S&W into building a .357 Magnum on the S&W "K" frame .38.
The idea of the .357 Magnum Model 19 was, a cop would have a smaller, lighter gun than the bigger S&W "N" frame models, BUT could still shoot .357.

In those days, cops usually practiced with standard .38 Special, and loaded up full Magnum ammo for carry on duty.

Things changed in the 70's when police departments started requiring all practice and qualification to be with Magnum duty loads.
The "K" frame began to have problems with premature wear and tear when shooting a steady diet of full charge Magnum ammo, especially the hot 125 grain ammo.

What happened was, the hot 125 grain ammo began to erode and often crack the barrel's forcing cone, and the gun generally got loose and needed more repairs to keep it in shape.

This is why S&W brought out the beefier "L" frame Model 686.  
It has a larger cylinder, a frame that's been beefed-up in key points, and has a barrel with a thicker forcing cone.

This does NOT mean that you can't enjoy and shoot a S&W "K" framed revolver.  They will shoot a good many rounds and last for many years.
What you can do to help things along is to shoot mostly .38 Special ammo, shoot mostly 158 grain bullets for Magnum ammo, and use as little of the 125 grain stuff as possible.

Bottom line is, if you intend to shoot LOTS of hot .357 ammo, and 125 grain at that, you might be better off buying a "L" frame 686.

If you want a good Magnum revolver that's lighter, and easier to conceal, the "K" frame is excellent and was THE police gun for 30 years.
Don't buy into the internet hype that the "K" frames will fall apart if you shoot 100 rounds of Magnum through them.....They won't, and are one of the finest revolvers ever built.
They were just a little too small for massive amounts of hot ammo.

As to the Colt Trooper Mark III and Mark V.
The Colt Mark III was Colt's replacement for their older model guns like the Trooper and Official Police.
Those older guns required extensive hand-fitting JUST to work properly, and Colt was no longer competitive due to the expensive hand labor.
Of these old style guns, only the Python was left.

The replacement was the Mark III series, introduced in 1969.
This new design was made in several models, including the Trooper Mark III, the Lawman, and the Metropolitan Police, among others.

These new gun were the worlds first machine-fitted revolver, in that unlike the older guns, the parts weren't made over-sized, then hand-fitted.
In these guns, the parts were made to a VERY close spec, and could be assembled by pulling parts from a bin until a fit was achieved.

Due to the design, these were extremely simple guns, made of large, durable parts.
Unlike the older Colt's, the Mark III was intended to be repaired by replacing parts, NOT re-fitting them.
To that end, the Mark III used "sintered" steel parts, made by injecting powdered steel into a mould and heating.  When the mould was opened, the part was virtually finished except for case hardening.

This manufacturing and surface hardening makes it impossible to refit, alter, or even polish internal parts due to the extremely hard, thin case coating.
Any cutting or polishing will break through the hard surface and expose soft steel, ruining the part.

The Mark III was also the first modern revolver to use a transfer bar action.  
This transfer bar system was so strong, simple, and safe, virtually every revolver invented since uses an almost exact copy of the Colt design.

The Mark III and later model Colt revolvers are so strong, Master gunsmith Jerry Kuhnhausen considered them to be the strongest mid-frame double action revolvers ever built, due to Colt's superior forged and heat treated frames and cylinders.

The Mark III and later guns have only one "weakness".  
If dry fired extensively, the firing pin "MIGHT" break, and this requires a trip to the factory for a replacement due to the job requiring special presses and support jigs to replace the pin.
A firing pin replacement CANNOT be done locally, no matter what a gunsmith may say.
The "fix" is to use snap caps for dry firing.

In 1983, the Trooper Mark III was upgraded to the Trooper Mark V.
The changes were:
A new vent ribbed barrel.
a shorter, rounded steel grip frame.
A new, short action hammer and trigger, made from cast steel instead of sintered steel.
A new, longer mainspring and a relocated spring seat, which along with the new hammer and trigger was intended to improve the trigger pull.

In the mid-80's, during the big Colt strike, Colt briefly made a Mark V as the "Peacekeeper" which was simply the Trooper Mark V with a dull black, unpolished finish.

In 1987, Colt did a slight redesign of the Mark V and introduced the King Cobra.
The only difference between the Mark V and the King Cobra was the KC had a different design barrel, and was first offered in stainless steel.  
The basic action and frame are the same, and all parts will interchange.

In "feel" the Colt's are different from the older Colt's and other brands like the S&W and Ruger.
The actual action is more like a S&W than the older Colt's, but the feel of the trigger action is different than both.
Most people like the later Colt action's feel.

As far as owning either a S&W Model 19 or a Colt Trooper Mark III or V:
The S&W typically has a trigger most people like better, and the action can be tuned by a good pistolsmith to a higher level than the Colt.

The S&W has a HUGE number of holster, grips, and accessories available for it. About anything made for a DA revolver is available for the "K" frame.
The supply of accessories and grips for the Mark series is more limited, but grips and holsters can be found without too much trouble.

The Colt Mark series was specifically designed for unlimited .357 Magnum ammo, and has a larger diameter cylinder, and a beefier frame and barrel.
As such it can be fired with unlimited amounts of Magnum ammo.

Due to the stronger Mark series and Colt King Cobra, and Colt's preferred heavy lugged and ribbed barrel design pioneered on the Python, S&W specifically designed the 686 to be a virtual copy of the Colt's barrel, cylinder, and frame size.
Because of the popularity of the Python barrel design, S&W along with virtually every other revolver maker have more or less copied it as closely as they can get away with.

The Mark series is a much more durable gun than the S&W Model 19, and will last for a lifetime, even shooting Magnum ammo.

The S&W can also last a life time, but NOT if shooting really extensive amounts of hot ammo.

Holy crap, that was as educational as reading an encyclopedia.  Thanks.

No need for me to add much more except I carried my 19 as a duty weapon in uniform and undercover

I still have the gun 25 years later and it work just fine

I did not shoot much 125 .357 Mag

I like 158 ammo in .38+P or .357 Magnum

I guarded celebrities and Presidents with it and it NEVER let me down

Quoted: I guarded celebrities and Presidents with it and it NEVER let me down

Looking back.....if you were guarding Hollywood celebs, you could have used a lot less reliable gun -----we wouldn't have minded.

I had a M19 that I think had suffered from some of that 'erosion', it would send hot gas back at me when shooting.  Dad has a M66 (essentially a stainless M19) that is a wonderful pistol.  I have also had a 686, and will be getting another.  All were very accurate, but my old M19 was the best, it was scary how accurate I could shoot that thing.