I have a Encore Pro Hunter that I have been tinkering with for a couple years now. I originally purchased it as a 20 ga. slug gun. Which it works very well as. However, ended up getting a 25-06 Rem. barrel for it (barrel is a TC Encore Pro Hunter). I have at times experienced vertical strings. Not at every range session though. At some sessions it would shoot great and some I would get vertical strings. I was switching back and forth between rifle barrel and slug barrel, so I am not sure if that had anything to do with it. I ended up installing the Bellm oversized hinge pin (1x), the Bellm lock up spring, and the Bellm hammer spring. I also put a new stock and forearm on the gun by Tony's Forends and Grips. So far in my testing, the gun has been very consistent. The rifle barrel usually shoots .75" groups at 100 yards (5 shot groups).