Need a quick favor for a race rack project..

I have a bedrug in my bed so I dont have access to the bed bolts and need a quick measurement.

Can one of you guys tell me what the measurement is from the bulkhead to the 2nd set of bed bolts, from the bulkhead. From this view they appear to be around 18 inches from the bulkhead, but I need an exact measurement please. Thanks in advance!