Have a STAG upper and a RRA lower, when pinned in there is no front to back movement but a little side to side movement. There is also maybe a .010 to .015 gap between the two, I want to use this for my SPR project (scoped etc.) is this going to affect accuracy or is it ok. I read about tight pairs that people can barely put together..it's got me thinking.

sounds normal to me.

And it won't affect accuracy.  

Some people put accu-wedges in their lower in attempt to tighten it up, but in my opinion it's a waste of money and only makes take down that much harder.

Think about it, a loaded magazine has the exact same effect as an accuwedge as the pressure from the magazine spring will push the cartridge up against the bolt carrier, which in turn pushs the upper upward, exactly what the accuwedge does.

And you may say but it'll be loose when the mag is out or empty.  But then...why does it matter you can't shoot your gun when it's empty, so the concern for accuracy is none issue.