The Trooper Mark III is astoundingly good quality, especially considering it was Colt's "Budget" revolver at the time.
The bluing makes anything done today look really bad.
The Trooper III was available in blue, bright nickel, and in satin Electroless nickel, also known as "Coltguard".
Calibers were .357 Magnum, .22LR, and .22 Magnum.
Barrels were 4", 6", and 8".
The Trooper Mark III and the versions of it like the King Cobra were considered by Master gunsmith Jerry Kuhnhausen to be probably the strongest mid-frame revolvers ever made.
Kuhnhausen thought this was due to Colt's superior forging and heat treating of the frame and cylinder.
As above, an "occasional" firing pin MIGHT break if the revolver is dry fired extensively, and this requires a trip back to the factory for replacement.
To solve this possibility, use snap caps for dry firing.
The S&W ejector pin must be bigger in diameter, since the cylinder latch pin is inside.
The Trooper Mark III pin is plenty strong enough.
The Trooper Mark III was the world's first "machine fit" revolver, in which parts were made to close specs, and the factory selected parts from bins to assemble a working revolver.
The older guns had parts that were filed and stoned to a fit.
To repair the older guns, parts could often be re-fitted to repair problems, but the Trooper Mark III simply has a new part installed.
One caution: The parts in these later Colt revolvers have parts that are case hardened. DO NOT polish, grind, or attempt to alter ANY parts, especially in attempting to improve the trigger pull.
ANY amount of this will break through the case hardening, and the part is ruined.
If you want to improve the trigger, buy a spring kit, which has a lighter mainspring, and trigger spring.
In total, the Trooper Mark III/King Cobra series guns are absolute tanks, and about the only problems are caused by abuse.