R-27 is the first sea-based small-size missile of the middle firing range. The missile incorporates a combination of unique technical solutions that became classical for submarine-launched missile building and allowed to radically reduce the weight and sizes of missiles and launchers, improve combat and performance properties. The arrangement of its engine inside a fuel tank became a fundamental decision in making the missile small-sized (leading designer A.M.Isaev). The factory-made fueling and ampulization of tanks by welding, full automated control of prelaunch preparation and launch were implemented. The following new principal solutions of submarine-launched missile building were applied to the R-27 missile: wafer-type shells, rubber-metal shock absorption systems, a combination of different functions in one structural element, completely sealed bimetal undetachable adapters, etc. The missile firing range increased by nearly 2 fold, the firing accuracy improved, the missile length reduced by more than one third, the missile silo volume reduced by 2.5 fold, the launcher weight reduced by more than an order and that of the missile by about one third, the ring gap volume decreased by about 5 fold.