This is a relatively easy-to-build anti-Grineer setup that should be able to take you through a decent chunk of the game.

Following is a brief explanation on why I chose the mods:

• [Infected Clip] and [Stormbringer] combined produce Corrosive damage, which is highly effective against the Ferrite armor used by most Grineer troops. This essentially provides a 75% damage boost against most units you will encounter.

• [Point Strike] and Vital Sense take advantage of Dex Sybaris' high critical chance, significantly amplifying the damage output.

• [Split Chamber] has a 90% chance of firing a second bullet with a single shot (firing up to 4 bullets with a single pull of the trigger). If you are able to rank up a Serration to level 6 or higher, however, replace Split Chamber with Serration

-[Serration] simply adds extra damage to

If you are able and willing to invest Formas to chance mod slot polarity, you can use one Forma for [Split Chamber]'s slot and then equip a rank 8 [Serration]. This increases the base damage to 936.3, the average damage per hit to 3,721.9, and the burst damage to 15,507.8. If you are able and willing to invest 2 Formas, you can also use one for [Serration]'s slot and rank up [Serration] to rank 10 (This increases the burst damage to 16,477.0).

However, [Dex Sybaris] will not be the best weapon for taking out Grineer in general, since Puncture damage (which [Dex Sybaris] does not specialize in, unfortunately) is more effective against both types of Grineer armor (Ferrite armor has a 50% Puncture damage boost and Alloy has a 15% Puncture damage boost). If you are looking for low MR weapons specializing in Impact, I would recommend the Hek (MR4) or the Boltor (MR2)

Please let me know if you have any comments/suggestions in the comments!