If the dude that posted his 600 yd shot grouping using a 4-12 Crossfire II can shoot like that with it...it definitely can't be all that bad of a scope. I ain't worried that it's going to be junk and I wasn't after the best scope money could buy in the first place. If you recall I was after the cheapest, decent scope for distance shooting...and the optimist in me says I found it.
Your scope is not junk. It will hold zero, and track. It does not have the the internal travel to get you much past 600 yards. Had I known your max range was 600, it would have been my recommendation, but when you mentioned 1000, that ruled the 6-18 out.