I just got my first AR and I have a question regarding the use of a red dot. It is currently set up with the regular front sight and a magpul flip up rear. I am considering going with a Bushnell TRS25 red dot sight. Gun is just for fun so don't want to spend a bundle on a high end optic. My question is will I need a riser to use the red dot? I would like to be ale to use the irons thru the optic if needed. Thanks!