Rifle Scopes Kahles

The Kahles 624 has 26 mils of total elevation adjustment, correct? You should be able to zero at 100 yards with a rail/mount combo of 40 moa. Should be at or near the bottom end, but should still be able to get a zero.
 
It would be damn close (my very rough estimate would be 1.3 MILs up from where you need to be). Some erectors have extra range in them, some don't. The specs sheet won't specify this generally.

Like Bkultra stated - check your zero stop and make sure it's not creating an artificial stop when you truly still have more downward erector travel remaining. Worst case, get a 0 MOA (you would probably be ok with a 10MOA if you wanted to risk it).
 
As long as you don't really crank on it. If the zero stop is "disengaged" and you go down as far as you can gently then that's all you can do. Logically, no forcing anything.
 
I just took my 525 with a 4601 and Defiance Deviant w/20MOA and was able to sight in at 100. I had 26.4mils of useable travel which on my 6mm gets me out to 2100+ yards as of yesterday. I have not decided if I will keep it or go back to a 0MOA.
 

How much total travel do you have when it’s bottomed out when you are attempting to zero?

If it’s much less than what the total travel I’m the optic is supposed to be, then you need to adjust turret to different zero stop, or there is something wrong with the internals.