I know they are very similar but what is the differences?Can you use mags interchangably?

nothing similar other than both are rifles/carbines , gas piston operated ,chambered in the m43 round, and of russian design.

different in so many ways!

the sks was a "stop-gap" design that was outdated pretty much as soon as it was adopted-SKS45. quickly replaced by the AK47, both those numbers are years. the SKS has gone nowhere really besides a few failed chinese upgrades. the AK has evolved a few times into a modern assault rifle. the sks was never an assault rifle it was a military battle rifle chambered in a mid powered cartridge.

lots of good info out there and right here on ar15.com

+1, The sks was designed to replace the SVT 40 as the standard rifle for the Russian Arm forces.

designed in 1943 by Sergei Gavrilovich Simonov


The sks shares many designed features of that of the PTRS a self-loading anti-tank rifle, the 14.5 x 114 mm . Also designed by Simonov. The only comparisons with it and the AK are two, they both fire the same round and they are both gas operated.

PTRS (you can see where he got some of his design ideas for the sks)



The larger capacity, ruggedness/reliability, and the select fire ability were some of the reasons why the AK eventually took the SKS's place in Russian military arms.  IT should be noted though, the SKS is still used for the honor guard to this day.

Not the same at all.

The "S" and "K"

Removable mags and 20 more rounds.