Waste of time and money - NCStar AR-15/M4 Quad Rail Handguard

I bought the mid length hand guard after replacing my carbine barrel and gas tube with a mid length.
it was not the quick snap in installation I expected. the handguard appeared to be to long so I found and watched the instal video which shows the forward end of the handguard goes around the outside of the forward handguard cap. HOWEVER, easier said than done. The outside diameter of the handguard cap was larger than the inside diameter of the handguard. What I thought was going to be a small adjustment with a jeweler's file turned into 3 hours of major surgery with the dremel. It is on but it's still not right.