I can't say what a good group is, but I can tell you I am averaging about 1.25" bench rested at 50 yards with my bone stock Disco .22. Some under an inch, an occasional 2" or larger group. Often I get 2 or 3 pellets touching, but the fliers open up the group.Wind can play havoc. We had some pretty good gusts yesterday, which opened one group up to 5 inches !I'm not sure if the fliers are me or the gun. Here is a review that claims 0.5" or better at50 yards: https://www.pyramydair.com/blog/2008/01/the-benjamin-discovery-part-2-accuracy/Funny, I see a bit better accuracy than they state in the article at 30 yards, but my 50 yard shots are a bit disappointing.
I must have a one in a million Disco. My stock Disco. using JSB 18.13grn. Heavies is grouping at 50yds. prone using a bi-pod on average under half an inch on windy days and in perfect weather under a dime or penny most of the time (as long as I do my part) and at seventy yards under an inch.
What is a good group for a .22 Disco at 50 yards?
I have found that my completely stock disco likes JSB 18g pellets. I shot 2 - 5 shot groups at 50 yards the other day that I could cover with a quarter. I was setting in a lawn chair leaning on a outdoor table with a rolled up towel for a rest. Here are pics.