This build is for a post [Blood Rush] and CO nerf, aimed at Grineer with Viral.

The Riven can be changed, but I personally prefer at least a +range +element.

Using the Sac mods, [Blood Rush] and [Gladiator Might] you [Reach] 296% CC for standard attacks. Without external mods (Gladiator mods on your Warframe), abilities or a Riven with CC this is pretty well guaranteed red crits.

A Riven with CC that is greater than 110% would allow you to achieve this without Gladiator Might, but this works better IMO because of the CC and CD gain from a single mod. The only better option would be Range/Cold/CD for a similar product.

If altering the Riven for a CD vs MD, replacing GM would result in 260% CC.