[bhale187]

Here's a few options that don't involve risking ruining your G27, big range in prices

http://www.opticsplanet.net/caa-glock-under-barrel-rail.html

http://www.beamshot.com/mounts_p_mounts.html

http://www.opticsplanet.net/beamshot-ut1-lasersight-accessories-mount.html