Zeroing DPMS LR-308 without 25 yard range

[brick13]

Good afternoon all, 

I installed typical iron/peep sights on my 308. The one time I had access to a range, the front post was too short to zero the rifle at 25 yards. I now have a center point laser bore sighter by Simmons and I have 40 feet inside my house. To get reasonably close, where would I put my aim point on the supplied DPMS target? Here is the one time I was able to get to the range?
love the gun!!! Reloading 308 for it.

thank you, bill

[98Z5V]

Plug your info for your load and gun into JBM Ballistics (free online program), for that 25 yard zero.  Look at what is says the drop is for 100 yards.  That's what you need to zero for, whatever the plus of minus is.

Zero that, at 25 yards, and you'll be on at 100.