The Seekins Precision SP3R M-Lok Rail System 15in 0260500015 will work with a Ruger Precision Rifle if you purchase the Ruger Precision mounting nut.
This Seekins Precision SP3R M-Lok Rail System is not compatible with the Ruger Precision Rifle without purchasing the Ruger Mounting Nut.
Seekins does not provide an exact dimension, however some users have reported being able to fit a 1.5" diameter suppressor under the handguard with just a few millimeters of clearance to spare.