I have cut down all 3 of my Pardners (12ga and 2x20ga's) One of the 20's is 18.5" and the other 2 are both 20".
I have scoped one of my 20's and use it for shooting slugs. It shoots very well out to about 70 yds. At 50 yds. it will shoot 3 Sluggers into a baseball sized group.
I haven't patterned the 12 or 20ga. that are cut down to 20" but I have taken gray squirrels at 30+ yds. with both of them after cutting them down. The 12ga. shoots Sluggers good too but kicks like a pack mule
I haven't played around with the 20ga. cut to 18.5" yet... I would imagine it will still knock down some game. Right now it's looking like it's gonna be my 4 wheeler gun.
Cut down Pardners make for a nice shooting, light carrying shotgun and the 20's are easy to drill and tap for a scope if you see fit to do so.
I had a .410 Pardner too that was cut to 20" (it became the stub for my 32-20). That gun was a real good slug shooter and I think it made for a better small game gun after the cut down.
The thing about cutting them down is that you can always have them threaded for tubes if you want to and you still have a great carrying woods gun.
Have fun with it... Pardners are like the Swiss Army Knife of the gun world... You can do anything with them.
Spanky