In your face? The human eye has a built in zoom lens so if something is clear you can see minute details. With poor vision or a fuzzy sight picture magnification alone won't help. It's like looking thru dirty sunglasses at something 10 yds away.
Now with a quality clear optic and thin reticule you should be able to shoot 1MOA at 1x so a 4" group at 4 power is possible. You can also easily see a 1/4MOA hole.
Having said this 25-50x should be where you want. A good nightforce scope will run you about $2500.
At 100 yards a 12x optic can make out .22 caliber holes, so I'm not sure why your 16x isn't doing the job. Have you adjusted the parallax and/or focus?
I figured Id throw my 2 cents in on this one.. ..... Hope this helped.. ooo... and if anyones looking, I have a Burris XTR 6-24X50 Im selling right now ------ now that thing will let you see some holes at 100!
What are you asking for your scope? Picatinny mounts included? Why are you selling?