Nerf Caliburn - Railgasm/Universal Handguard Integration

Threw together a quick edit of BSHROUD.stl, handguardset-102317.stl, frontblock-102317.stl and primeblock-102317.stl so that the argus handguard and railgasm barrel shroud should work together without having to cut parts up.

Tested now and it all does what it should.

As per request I threw together a new file with all the bshroud files merged.