Hello Alan:
I too am a Ruger 10-22 fan... I picked up a "vintage" carbine, and it shot well... but not great.
As a tinkerer... I looked at what to do next... better ammo, the usual springs / trigger stuff. It helped a bit, but....
I have a basement machine shop so gauged the barrel headspace and chambering, my original barrel was sloppy...
I took off 10 thou from the breech, which helped a bit, but not enough. Chamber was big...
So, I ordered a Ruger match barrel from Midway, and a Magpul Stock.... when rebuilt, my 1990?... ish 10-22 does less than about 0.3" at 50 yards and 1"-ish at 100. That's with Aquila STD VEL ammo... keep it below 1080fps... I have an old and $25 6-25X scope, cracked optics, ugly, but works, and I can literally kill flies at 50 yards.. that's with $6 a box for 50! The Ruger barrel has a tight chamber, and the stock is a much better form factor for me, I'm 6-3 and need the LOP. A really fun rifle, kind of sad that only the receiver is standard!
Cheers!
Steve1