"Assault Rifle" , I think can be used to cover a whole Lot of different guns from different time periods.
Spencer repeating carbine from Civil War, fast light and easy to reload, popular with cavalry on bothsides.
Winchester lever gun. Some did show up in the civil war.
I think the best little now use of it was between Turkey and Russia.
I forget When, but, do recall the Turks ordered and recieved a large order of (I think 44 cal) Winchester lever action military muskets.
In the battle, with one soldier shooting and 2 Reloading, the Turks badly shot up a Russian Army armed with single shot muskets.
The Russians fianlly did win but, at a horrible cost of lives. I think they litteraly Slaughtered the Turks that used the Winchesters.
After that, the Rissian army placed an order for similar Winchesters. Not sure if the order was totally completed.
Don't forget also in the expansion of the American west, the repeating rifle played a big part. As did the various revolvers.
While it doesn't have a Large magazine capacity compared to today's modern assault rifles, I think that the lever action rifle does have a place.