I have a straight model 19, ser# K343926.
Can you tell me when it was made?

K343926 is circa 1958.
A "straight" Model 19 is also referred to as a Model 19 or a Model 19 no-dash. 1957 was the year S&W transitioned from named revolvers to model numbers. Prior to its designation as a Model 19 it was known as The .357 Combat Masterpiece. "Combat" generally refers to a 4" barrel.

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K343926
Closest SN on my list is K3454xx which shipped in 8/59
K317,823 – K350,547...1958 (production)

" it was known as The .357 Combat Masterpiece"
It was known as the Combat Magnum.

At least it wasn't referred to as a non-straight 19...

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