Machine Gun Liner Bond Strength

Abstract : Bond strengths of two Stellite 21 liners in the M2 0.50-cal. machine gun have been measured. Both liners were obtained from machine-gun barrels that had been retired from service. Liner bond strength from one of the barrels was measured to be ~750 psi. The other liner fell out of the barrel during sectioning, and its bond strength was much lower. Simple calculations showed that a bond strength of 750 psi was compatible with a shrink-fit process. In this case, the bond strength was shown to be sufficient to resist the forces on the lands and grooves of the liner due to spin-up forces on the bullet.