There are a lot of facters involved here, you stated after some gunsmithing, that could be a big part of accuracy, are the stock screws tightens properly, is the barrel clean or is it to clean is it a new barrel, just ofhand I'd say that a fair 243 should have better groups than a quarter lets say that a quarter is about a inch and a quarter, Dose the gun surprise you when it goes off. are you squeezing the trigger, If you aren't having any flyers or at lesst not more than 1 per grouping, I'd say that if you are getting 1 1/4 inch groups that your trigger finger is probably fine, clean your barrle, and after about 10 shots try another group, and don't forget the wind, shoot early am or evening when wind is down. you might see your groups 3/4 inch or better then you have something. to get better than that you might have to practice practice practice.
Hey I just measurd a quarter, its smaller than I thought, I still say that you should do better, but a quarter is pretty good, more than good enough for a coyote gun, ifn your shooten prarie dogs better get it down a little more unless you found some uneducatd ones