Abstract: A thermally stable polycrystalline diamond compact is created by (i) preforming an annular thermally stable polycrystalline from a diamond plate, (ii) preforming a substrate with a projection that has an interfacial mating surface that is a negative topology of the annular thermally stable polycrystalline, (iii) and brazing the two components together. The resulting polycrystalline diamond compact can be made thermally stable because cobalt and other catalysts can be leached out of the thermally stable polycrystalline. The thermally stable polycrystalline can be attached to the substrate by brazing, which due to the topology of the thermally stable polycrystalline and the substrate with a projection will unexpectedly have sufficient blaze shear strength to be used in demanding applications.

Abstract: A buffer tube for firearms, including assault rifles, carbines, shotguns, and other rifles is disclosed. The floating buffer tube comprises a recoil mitigation mechanism, including a helical spring or an elastic or viscous energy absorption device, and a buttstock mounting bracket mounted outside the buffer tube. The buttstock mounting bracket can rotate relative to the buffer tube, which changes the axial angle of the buttstock relative to the firearm. The angle can be locked under an expansive force by forcing a bolt or pin into grooves to select the proper axial angle of the buttstock relative to the firearm in the field without the user having to disarm himself to perform the angle change.

Abstract: A cobalt-boron alloy is used as the matrix in a polycrystalline diamond compact. The matrix is hot isostatic pressed with tungsten carbide to form a substrate. The substrate is then high-pressure, high temperature sintered with a diamond powder, preformed and acid-leeched diamond plate, or another ultra-hard material in a press mold to sweep the matrix, thereby creating an ultra-hard polycrystalline compact at a temperature 400° C. lower and with less graphitization than conventional techniques using cobalt binder. The compact is stronger and has a longer useful life than conventional compacts.