M1 Garand National Match Rear Sight Aperture Hooded 1/2 MOA fits M14 M1A NM .0520 PeepNational Match Hooded Rear Sight Aperture for M1 Garand M14 M1A . Apertures can be used on M1A/M14 and M1 Garand rifles with NM2 / NM2A marked Sight Bases (Not for use with standard sight base). Aperture allows elevation adjustments to 1/2 minute (MOA) adjustments by turning the hood. Aperture features a peep hole diameter of 0.0520". New production made in the USA. * Fitting/stoning is required as apertures are made over sized for custom fitting to your base. **Install / Fitting Instructions can be viewed/downloaded from "Documentation" link, top right above.