Check out Kenton Industries. http://www.kentonindustries.com/pics/ttctypes/
They are very well known and make excellent custom turrets. The may be able to make one for you if you decide to get one.
In case you have never made a drop chart before you need to do it with your rifle with the load and bullet weight you are planning to use.
Do not trust a computer ballistics program to have your turret made from. My rifle which shoots a 6mm Norma BR. with Berger 105gr. VLDs and CCI4 primers and Varget powder does not shoot like the JBM ballistics computes. My zero is 200 yds. and JBM says my bullets should drop 7 inches at 300 yds., but it actually drops 8 inches. This difference would make a turret very inaccurate at longer ranges. What the guy at Vortex did was to enter my actual drop measurements into their ballistic program and then changed the velocity until my drop numbers matched up. Then when the custom turret was made it reflects the actual bullet drop at all the ranges.
and they are dead nuts on.
They made the turret with numbers going from 2 then 3 then 4 then 5 and so on for every 100 yds. In between each number there are 3 tick marks. Each tick mark equals 25yds. So the tick marks represent 25+50+75 yds. in between the 100 yd. numbers.
Hope I have helped and good luck,