[SOLVED] Will an MSI 1060 6GB X+ fit inside an HP compaq pro 6300 mt?

Solution
If this is what your case looks like inside, it is a BTX case/motherboard. As a result, the body of the gfx card will extend up from the PCIe x16 slot (opposite of how it would lay in a standard ATX case). So you need to measure the distance along the PCIe x16 slot from the expansion slot covers to the first obstruction you come to. That appears to be the CPU cooler. Then you need to find a GTX 1060 short enough to fit in that distance. Something like this would fit.

But first, what PSU do you have? If it is the 320W stock PSU, it is too weak to power the GTX 1060 safely.

Update: I just saw you listed the card as the MSI X+. That card definitely will not fit.
If this is what your case looks like inside, it is a BTX case/motherboard. As a result, the body of the gfx card will extend up from the PCIe x16 slot (opposite of how it would lay in a standard ATX case). So you need to measure the distance along the PCIe x16 slot from the expansion slot covers to the first obstruction you come to. That appears to be the CPU cooler. Then you need to find a GTX 1060 short enough to fit in that distance. Something like this would fit.

But first, what PSU do you have? If it is the 320W stock PSU, it is too weak to power the GTX 1060 safely.

Update: I just saw you listed the card as the MSI X+. That card definitely will not fit.
 
Solution
MSI model would be too big to fit in as compact design of your cabinet also above mentioned mini version is good enough fot 1080p gaming as difference is not big in most of the games however I would suggest you to look at Zotact 1060 mini version - it is compact and well built also less expensive in all 1060 cards.