I think you mean a handgun machine rest. A machine pistol rest is for a class III weapon.
I'm pretty sure the HAMMR was discontinued. Either it didn't sell well or it caused a lot of complaints.
The Ransom company still makes their product. It is here
. A friend of mine used to own one, but sold it long ago. We found, in testing 1911's on it, that accuracy off sandbags was sometimes better and had a Hoppe's pistol rest that worked fine for that. The reason was the Ransom (like the HAMMR) hangs onto the grip frame. A pistol can have poor slide to frame tightness but still lock the barrel up pretty consistently into the slide which has the sights on it. Thus, the barrel and sights may be lined up for accurate shooting when the grip frame is not. In a gun with the slide tightened to the frame, though, it was pretty good.