C-301
The C-301 (also known as HY-3, with NATO reporting name CSSC-6 Sawhorse) is a large supersonic coastal defense anti-ship missile (AShM), and it is the basis on which two other members of the C-300 series AShM C-302 and C-303 developed from. C-301 is the first member of the C-300 series AShM with four solid rocket boosters and two ramjet sustainer engines located aft of the missile body. When the booster motors have accelerated the missile to past Mach 1.8, the kerosene-fueled ramjet engines kick in, accelerating the missile to a cruise speed of greater than Mach 2.0 . The maximum range is 180 km, and it can fly below 50 meters at its cruise altitude. The missile is programmed to descent from cruising altitude to a much lower altitude before the active-radar terminal phase begins, then dive onto the target just prior to impact. The general designer of C-101 is Liang Shoupan, who is also the general designer of another Chinese supersonic AShM C-101. The C-301 only saw very limited service in the People's Liberation Army Navy as a coastal defense missile, and a stopgap measure in a limited scale production as more capable missiles becoming  more widely available. C-301 is also used as a stopgap measure to replace the obsolete C-601 anti-ship missile, the air-launched version of the Silkworm missile carried on the Xi'an H-6 bomber (with one missile under each wing, like the C-601), until more potent supersonic anti-ship missiles become widely available. C-302. An improved C-301 version, called C-302 was later developed as an upgrade. C-302 is highly digitized and fully solid state, and the cruising altitude is also decreased further. After entering Chinese service in very limited numbers for evaluation purposes, C-302 did not enter mass production, due to  the obvious shortcomings of liquid fuel rocket: the operational cost is high because periodic maintenance is required much more frequently and the safety standard during handling is also higher in comparison to solid rocket powered AShM. The advantage of supersonic speed can be achieved via ramjet powered AShM. During its very limited service with the Chinese navy for evaluation, C-302 was only known to be land-based, though in theory, it could be deployed by large aerial platforms. However, unlike its smaller cousin C-101 that can be carried by numerous aircraft in the Chinese inventory, the C-301 and its upgrade  C-302 can only be carried by Xi'an H-6 due to their large size and weight. It is safe to conclude that as newer missiles entering services in greater numbers, the C-301/302 would eventually reduced to a sole coastal defense missile. Just like its smaller cousin C-101, Chinese claim that other type of seekers such as infrared imaging and television seekers have been successfully developed for the missile, but the status is rather uncertain. C-303. The last member of C-300 series AShM is C-303, which differs drastically from C-301 & C-302. The C-303 differs from the other two AShM in that its  flight path: instead of sea-skimming, C-303 would climb to 20 km altitude first before transition to level flight, and after cruising at 20 km altitude for most its journey, the seeker of the missile of would be turned on around 50 km away from target, dive down on its target at the terminal stage in a near vertical dive in a way similar to SS-N-19. C-303 can be either launched at a slant angle like most other AShM's, or launched vertically like a space exploration rocket. Just like its smaller cousin C-301 & C-302, C-303 only entered Chinese  service in extremely limited numbers, mostly for test and trial purposes, due to the inherit drawback of liquid fuel rocket that prevented C-301 & C-302 AShM from being widely adopted. Unlike C-301 & C-302, C-303 can only be land-based. It is rumored on Chinese internet that future Chinese supersonic long-range AShM developed & under development utilizes experience gained from C-303, but such claims have yet to be verified by official Chinese governmental sources and other independent sources. Original developer: CHEMTA (China Sea Eagle Electromechanical Technology Academy, 中国海鹰机电技术研究院, formerly the 3rd Design Academy of the Aerospace Ministry), China Precision Machinery Import-Export  Co. References. C-301