My first revolver.

Well played sir! For your information when the Colt Mk III was introduced there was some moaning from those purists who worshipped at the alter of previous Colt hand fitted actions and were highly skeptical of the introduction by Colt in this series of "sintered" internal parts. The Mk III was absolutely an attempt at Colt quality on a more blue collar budget. The attempt resulted in side benefits as well though. Time has to a large degree quieted the skeptics. No less an authority than Jerry Kuhnhausen, the author of "the last word" in shop manuals not only for Colt but S&W declared that the Mk III was the strongest .357 produced to that date. Regardless of internet blather and chest thumping, they give up nothing appreciable to the strength of Ruger's GP100.

It IS however prudent to ALWAYS use snap caps if dry firing. This is a frame mounted firing pin requiring a wildly expensive press to replace. The only known examples (example?) of this press reside in Connecticut at the Colt factory. For how much longer is anyone's guess. dfarriswheel has passed along anecdotal evidence that some of the firing pin batches may not have been properly heat treated and may be susceptible to breakage in dry firing without the snap caps. When snap caps ARE used the entire series has a reputation for robust longevity.

Expect hallmark Colt accuracy from this excellent barrel, and IMHO an action that while not as silky as a hand fitted Officer's Model, Python, etc. from the pre Mk III pattern is nonetheless consistent and when you get used to it, exceptionally well fitted for target/duty service. This would be my choice (probably seconded by many on a Colt forum) over a GP100 that would have cost 50% more.

The "collector" community has also "discovered" the Mk III's and at market they are experiencing a higher than average inflationary curve in resale price. This buy was a no brainer for sure.

Congrats!