i've had a similar prob w/ an older, worn 10/22........
the problem i found was the bbl tenon/reciever fit........this one's bbl had started to "droop", and was contacting the reciever extension at about 4 o clock position......was sending flyers everywhere!!!....lol....
i shimmed the bbl tenon up w/ some .003 stainless foil, and relieved and epoxy bedded the reciever extension to the bbl......... i'm still in the process of some other stock work on the rifle, so i can't give you exact specs on how it worked yet........ i did one quick check w/ it in the partial stock.....colibris @ 50'......it seemed to eliminate alot of flyers, but i'd done some trigger work also, one or the other seemed to help!....lol....
good luck w/ it, and keep us posted on what works...
skintback
ps: i was having alot of probs w/ extraction caused by the "droop"....... all of that cleared up when i corrected the bore/breech alignment.......