Herter's .357 mag

[Officer2312]

Hello, all
I have ended up with a Herter's .357, manufactured by Sauer & Sohn in 1966.  Been doing alot of research on the gun and it seems to be mostly an oversized '73 SAA. 
Here's my problem:  I know precisely squat about the SAA.  My first single action revolver...I've had all kinds of pistols and rifles, and work on everything, but never messed with a single action.  I noticed last night that when I cock the hammer all the way till it stops then let it go, she drops all the way to the firing position.  Doesn't stop at the full cock notch, or the half cock.  Now, if I cock it to full cock and slowly lower the hammer, like I normally do, is sets fine and dandy.  Have notice that if I move the hammer to half cock and pull the trigger the hammer falls. 
I don't know much about it, but I'm assuming that the sear and hammer probably both have some issues.  I believe I have found the parts, just wondering if anyone has any experience working on these-wondering if there is anything I need to be aware of before I dive into this project.  Any experience anyone has out there would sure enough be appriciated...
Thanks!

[gcrank1]

Might be the trigger return spring gummed up or broken. The sgl. action is very straightforward in hammer/sear function. Take it down and clean it out looking for issues as you go, it'll make sense to you.

[Officer2312]

Thanks for the help...I've been sick the last several days, and didn't get a chance to take it down till a few hours ago.  Looks like she's solid for the most part, but the full cock notch looks like it's been trimmed down. I'd say the previous owner tinkered with it to give it a really nice, light, short trigger pull.  Personally, I'd rather not have to worry about sending a round out into the great unknown involuntarily.
Probably gonna replace the hammer and the possibly the trigger as well... Gonna mull it around a bit...may just buy a bunch of parts and have spares...

[gcrank1]

I hate it when I find a ground back hammer, but all is not lost. Hopefully the angle is OK, just the tip of the sear (the end of the trigger) doesnt hang back in there quite enough. I have been able to get way back into the notch and deepen it with my Swiss files on a few. Mind you, this does not touch the sliding surface that the sear rides on, just the very back corner where it bottoms out, which is often not a square corner but rounded a bit. Another .005-.010" can make a big difference. BTW, I use a magnifier and Magic Marker on the steel to be able to see what is happening. If you do this carefully you wont hurt anything, may actually fix it and arent any worse off that before.
If you dont feel confident in doing this, PM me  .