Which model do I have?

[rossa]

Not sure if I have a Standard, Mark I or what. No bolt lock back lever, no markings saying which model, serial number starts with 17-, late enough that it has the imprinted warning on the top.
Under the left grip panel is stamped A-100.
Thanks in advance.

 

[peachhead]

Based on sn and a100 frame that should be a mark ii.
I am not as familiar with the ins and outs of the semi autos as I'm sure others are; I'm sure someone will correct me if I am wrong.

 

[rugerguy]

some of the the 1981 and 82 RSTs and the Mark I would fit that scenario, had the #17 prefix and if NO markings sound like a RST and whatever the barrel length may be,,,,Mark I HAD THE MARKING AS WELL AS THE ADJUSTABLE SIGHTS!!!
pictures would help but you got it pegged......

 

[rossa]

Haven’t heard of the RST before.

 

[contender]

RST.
Ruger Standard Auto

 

[GasGuzzler]

I have one that is early '80's and is really close to the line of demarcation. I don't remember which one mine is.

 

[NH Rugerman]

Fixed or adjustable sights? If it is a Mk II it will be roll marked as such, otherwise it is either a Standard Auto (fixed sights) or a Mk I with adjustable sights and should be marked as such….

 

[rossa]

Fixed sights. Maybe a Standard. Not a lot of experience with these guns, so I had never heard the term RST before. What’s the difference between the RST 4 and 6?

 

[bwct]

RST 4 = 4 inch barrel
RST 6 = 6 inch barrel

 

[NH Rugerman]

With the 17- prefix and fixed sights, it is a standard pistol…

 

[Highstandardguy]

RST 4 = 4 inch barrel
RST 6 = 6 inch barrel

RST 4 = 4.75 inch barrel

 

[rossa]

Thanks for all of the responses. I’ve learned a few things!