US WW II "Assault gun" (not small arms but SPG)

I'm reading cavalryman Harold Pagliaro's book, Naked Heart. What type of "assault gun" would accompany the US cavalry into combat? M8 Howitzer (M-5 Stuart chassis but with 75 m low velocity howitzer), M-3 Halftrack with 75 mm gun?

 

Depends upon the time frame. It could be the M4A3 105.

 

It's the M-8 (M-5 Stuart with 75 mm howitzer) that accompanied the cavalry units.

 

Does the M7 Priest qualify? I seem to remember reading about them accompanying allied troops at the Siegfried line and beyond into Germany. I can't remember which book.

 

"Assault gun" usually refers to a vehicle intended to deliver direct fire on the enemy. Self-propelled artillery like the M7 could do this but was most commonly and effectively used in the indirect fire role, behind one's own lines, taking direction from spotters, and largely safe from return fire.