A4 upper question

[mtls44555]

Hello, I have always wanted the classic look of a m16a4 but got a stag model 8 instead. Now I have enough cash for one but instead of buying a new rifle I would just like to get the upper and a new butt stock. Can I just put a Rock River Arms A4 upper on my stag lower without any issues? Sorry for the newbie question have not done a ton of research on this.

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=267

[Just.a.guy]

Any milspec upper *should* fit any milspec lower. There may be some manufacturing errors in one or the other that could cause it to not be perfect, but unless something is drastically wrong you should have no problems.

[MrPlink]

You wont have an issue. Stag is gtg