Baribal,
Old NRA rules, old artical. Any bullet under 156gr may be used for DCRA and Palma Competition, been that way for about 15 years. Trigger weight and max rifle weight is changing to reflect new ICFRA rules, likely by next season.
The iron sights we are talking about are in fact Vernier/aperture type target sights.
Johnny Canuck, There are many different rear sights and many different mounting options. Some are side mounted some are top mounted and several different dovetail styles.