Question about changing upper on an AR15

[jbflowers]

i currently own an xm15 with the a2 upper and im looking to go flat top so i can mount my eotech on it. the dilema im having is rather to buy just the upper with no barrel or buy a complete upper. what are the advantages/disadvantages of doing this ??? ive heard about possible sight problems if i just changed the upper and use to same barrel.

 

[dispatch55126]

The advantage of a complete upper is you essentially get a second gun. Since the lower is the same, you'll know the break and travel of the trigger. Also, it gives you the flexibility of deciding if you want to shoot traditional open sights or use the EOtech.

I you only get the receiver, you will again be stuck with just one option.

 

[MMcfpd]

The only reason to change out your receiver, besides financial considerations, would be if you just couldn't get the barrel/receiver combination you want as a complete upper.

Otherwise the advantages dispatch listed pretty much make the case for a whole new upper.