I just installed the bolt catch assembly into my RRA lower. All I have put together is the lower, I don't have to upper attatched. When the hammer is cocked back, the bolt catch moves just like it is supposed to, its under tension and moves smoothly. However when the hammer is in the non cocked position, when its resting against that front part of the reciever, its pushing on the bolt catch piece and it causes it to be very difficult to move. Is that normal?

Just got my answer doing a small search. It should never just slam onto the bolt catch, upon wich i have already had this happen when i was not careful. I read it can break the lower reciever webbing. So, I've decided to keep the hammer in the cock position, with the safety on. Is that ok? can I leave it that way for awhile? I just dont want it resting on the bolt catch correct? Right now the plan is to leave the hammer cocked, and the safety on for a few months until I decide exactly what I want for an upper.

Well the rifle is in the position normally if the safety is on. If the safety is on that's the only way the hammer could be, cocked. Don't worry about it, worry about getting  a good chrome lined barrel and chamber with a 5.56 chamber instead.

Leave it cocked....

Keeping the lowered hammer on the bolt catch won't cause any harm, all my complete AR's and lowers are stored decocked.  Reduces stress on the hammer spring.  Control the hammer to decock, DON'T let it fall with the upper and lower separated, or as you've discovered, damage can result.  Once the hammer is resting on the bolt catch, the bolt catch will have its motion restricted.  Perfectly normal and perfectly harmless...

You should see the nice ding I put in my preban NIB Bushamster lower when installing the trigger and I accidetly let the hammer fly forward and hit the reciever before I put in the bolt catch! [:p]