member 68 so that the outer end portion 116 of the upper projection 70 extends outside of the handguard bushing 80 when the barrel retention member 68 is in its fully seated locking position as illustrated in fig3 as best illustrated in fig2 and 3 since the portion 88 of the handguard bushing 80 is covered by the inner end portion 90 of the handguard tube 86 the inner end portion 90 of the handguard tube 86 has an elongated vertically oriented slot 118 that is substantially identical in shape to the slot 106 and is located to coincide with the slot 106 in the handguard bushing 80 in addition as indicated in fig2 and 3 the inner end portion 90 of the handguard tube 86 has a rectangular shaped aperture 120 that is located and sized to coincide with the rectangular shaped aperture 112 in the wall of the handguard bushing 80 these apertures 118 and 120 in the inner end portion of the handguard tube 86 allow the barrel retention member 68 to be inserted into the handguard bushing 80 and the barrel receiving nut 46 to secure the barrel 12 to the upper receiver 14 it will be appreciated that the handguard assembly 76 of the firearm barrel change apparatus 10 is the free floating type since the handguard assembly 76 does not touch the barrel at any point other than through the barrel receiving nut 46 as a consequence the m 16 type firearm 16 that uses this handguard assembly 76 should have better accuracy than the same m 16 type firearm with a conventional handguard assembly in addition the handguard tube 86 has an elongated slot 122 extending.