My SPR has mk4 med rings and a mk4 4.5x14x50. If u use the flip caps, they might touch. I just filed the bottom of the front cap and took care of the issue. W/o caps there will be around 1/8-3/16 clearance between the objective and the barrel. Of course if the scope tube is longer it would have more room due to the taper in the barrel. Hope that helps.