I have encountered problems fitting the lower (rear) handguard on a Model of 1917. The model of 1917 handguard will fit the P14 since the P14 has a smaller chamber diameter and the inletting on the Model of 1917 hanguard is more generous, but the P14 lower handguard will not fit the Model of 1917 as the inlet is smaller and prevents the handguard from seating correctly.