in my near 20 years of owning Glocks, and having owned several different models in just about every caliber offered (no .380), my Gen 3-37 is the most accurate Glock I've ever owned.
years ago when taking my CCW class, expecting to have to shoot at "combat" ranges and tho I had no plans of carrying the 37, I took the most accurate handgun I owned for the shooting portion of the CCW class.
when it came to the shooting portion of the class, the target was a piece of typing paper with a 1" red sticky dot at 10 ft., the instructor said he just needed something for his records showing we had shot the shooting portion of the course.
at the range, I was first up and shot a 10 round single hole completely obliterating the red sticky dot, several of the class member familiar with Glocks asked to shoot my 37 and a few more 10 round single holes were produced.
in close to 45 years of shooting, I've not experience anything like this, (well, I did out shoot a guy with his issue 686, he thought it defective until I proved it wasn't) and will be the reason I'll be buried with my 37.