Welcome to the Ruger Forum.
What you have is a early released gun because of the fluted cylinder. The front sight is also a little different, in that it is just a tad taller than the 22LR models and just about impossible to find,,, the 22LR height is easy.
The story goes;
Mr. Ruger didn't like the Bisley rollmark on the cylinder, and in an effort to get em out, said… "install fluted cylinders and ship em".
I personally am one that prefers the fluted cylinder vs the Bisley rollmark.
Top gun w/stags is 22LR, Bottom gun is 32HRM. (SN# 650-1697X)
Notice the darker color of the grips,,, the grips on these guns were made from a wood that is quite dark, but can have some reddish streaks,,, they were very nicely crafted and fit is usually very good, some of Ruger's best ever.
The bluing and finish was excellent.
Both of my guns are very accurate shooters.
The 22LR was never offered as a convertible, BUT I have found a 22MAG cylinder and it works perfectly.
Now for your hammer situation, it has most likely been harvested for another custom project, and a standard hammer swapped in.
Here is where it is going to get very interesting,..
Single Six Bisley Hammers, command a very big premium when they can be found,,, and supposedly they don't make them in Carbon Steel/ Blued anymore,
Ruger switched from Carbon/Stainless to only Stainless a few years back.
My suggestion is call Ruger, they will want your SN#. Let them know your gun has the wrong hammer and you want to get the correct hammer. They will want you to send the gun to them for the install, and you might even get a Carbon Hammer. Why do I say this?,,, I have seen guns come out since the Carbon / Stainless switch with CARBON, makes me think they have some. Will you get a answer on this question on the phone call ,,, probably not. Just not going to be info the CSR will know.
What ever Hammer you get, Carbon / Stainless it will be a correct Bisley Hammer for the Single Six,
FWIW; if one can find a Single Six Bisley hammer out in the world expect to pay $125-250. The shipping will be more from Ruger than the ~$35 they will charge you for the hammer.
Sometimes Ruger will ship it back on thier dime.
ALSO,,, While your on the phone with CS,,,
Ask them for a shipping pick-up tag, they will charge you (~$50+/-) but it will be a bunch cheaper than shipping it yourself.
The cheapest way to ship it is if you have a FFL DEALER that will ship it via USPS FLAT RATE.
This gun was/is a Single Seven BISLEY 327M that was shipped with a
Carbon Hammer well after the switch.
I swapped out the Bisley Gripframe to a RW Keith #5 Brass.
And drop the "flattop" from your description,,, a common mistake made by some. That style of top strap is original to the Old Model Single Six from day one.
There are not many New Model guns made with it, but you have one.
… A very pleasing aesthetic styling from days of old.
Flattops were/are the original 357 & 44 Blackhawks, and they were not called that untill the "protected with ears" of the rear sight Blackhawks were introduced.
1989 mfg.???
A little help with manufacture date.
My gun is SN# 1697X , mfg. is 1986.
1986 guns started at 16439 and ran to 27059, per Ruger,,, so if your last 3 are lower than 16439 that would be 1985.
… Info per
Ruger SN# lookup.
Either way your was one of the first shipped out because of the fluted
Thank you. I have the model number: 00630. Can you tell if Bisley or standard Single Six with "plough handle"? I am not concerned with cost of letter. Certainly a bargain at $10.00!
My error, 00630 is model number for .22lr. Model number is 06530 for .32 H&R magnum. I have both. No issue with the .22 LR.