The ranges are SUPER tight here, as SW really started making a ton of guns then, and most models shared serial ranges.
If it has a one or two digit number, and THEN a "D," and THEN some more numbers, (meaning the "D" will be either the second or third character in the serial, and all other characters are numbers) it is from 1977-1983 After 1983 the serials get crazy and will be in the format of three letters, and then four numbers.
These are model changes, meaning some feature or aspect of the gun changed a bit.
If you find the 10-1, or 10-8, or 10-XY, you can narrow it down a bit further.
t=356710 It has a lot of info that might be of interest to many of you.
K .38 Military&Police 38 Spl K .38 Hand Ejector (same as above, with adjustable sights) .38 Regulation Police (Square Butt) 38 S&W I .38 Terrier 2" Round Butt 38 S&W I .38/44 Heavy Duty (fixed sights) 38 Spl N .38/44 Outdoorsman (Adj.
10 by itself means started in 1957 10-1 started in 1959 10-2 started in 1961 10-3 started in 1961 10-4 started in 1962 10-5 started in 1962 10-6 started in 1962 10-7 started in 1977 10-8 started in 1977 10-9 started in 1988 10-10 started in 1988 10-11 started in 1997 (probably not this or later, since your gun is blue) 10-12 started in 1997 10-13 started in 2002 Using these tables together, you should be able to narrow down a decent range of when your gun is from.The serial number is 10D9723 and it has never been fired. I'm sure there are many experts who can narrow this down even further, but your best bet is to request an official Letter of Authenticity from Smith & Wesson.