Have tried this and the same model without " EFR ". There is an adjustment ring that will allow for parallax correction at different calibrated distances. The downside is that if you forget to set it for the correct distance your target will be slightly off. So it can be your best friend or worst enemy ! Mounted these on Kimber Montana's ( .325 WSM ) and Sako Quads to keep the weight and profile down. For close shots this version ( With EFR) will allow bullet holes to be clearly seen at 10 yards or so. Without " EFR " close focus is somewhat fuzzy but still useable. So what's the bottom line ? If you can remember to adjust the distance you get superior results. Should you be prone to forget, the simpler version or a fixed scope might be better.