The full-sized M17 vs. the more compact M18. The guns use the same interchangeable fire control unit and magazines– either flush-fit 17-round or 21-round extended mags. (Photo: Chris Eger/Guns.com)A report says the nation’s seagoing branch will go with the smaller version of the Army’s Modular Handgun System, the Sig M18, to replace legacy 9mm pistols.The Navy currently uses the M9, a variant of the Beretta 92F shown above, and the M11, a more compact pistol based on the Sig Sauer P228. The new M18 will replace both. (Photo: U.S. Navy) The Navy will phase out its current M9 and M11...