Welcome to the forum. The model 910 and 915 are the same gun. The difference is the 910 came with a 10 round magazine as per the Clinton assault weapons ban which limited the 15 round magazines to law enforcement use only. (Thank God it expired!
) Both guns are a lower cost "value version" of the 5904. There are a few minor differences such as rear sights, but most 5904 parts, including grips, will fit a 910/915. Grips from a 5903 or 5906 will also fit the 910/915. -Ed.