H&K Barrel Retaining Pin - 5.15mm

H&K Barrel Retaining Pin - 5.15mm

This is the barrel pin used for installing a new or replacement barrel. HK suggests using a new factory barrel pin when installing or reinstalling an HK barrel in the trunion. Each pin is slightly oversized for trunions that have been opened up just a bit too much, or when reusing a trunion, an oversized barrel pin should be used in place of the standard 5mm barrel pin.