I have a Chinese sks with a blade bayonet. Left side of resever shows a 22 inside a triangle and three Chinese characters, imported by ACT III, Greensboro NC. Could anyone tell me what arsenal it came from? Also, I didn't know sks rifles had blade bayonets. Is this a unique rifle?

Well not really,but the blade bayo is pretty nice compared to the more common spike bayo which started showing up on Chines SKS rifle around 1965 to 66 till the end of production. The blade bayo appeared on the first Chinese SKS rifle made at the Jianshe Arsenal Factory #/26\ these rifles have a four digit serial number with a letter or symbol without the three Chinese characters they were know as the Sino-Soviet SKS rifles. The three Chinese characters didn't appear on the receiver until after 1963

The Chinese had many different arsenals,Factory 22 was just one of them where it was located and what year your rifle was made cannot be reliably determined only the /26\ rifle can be dated. Some other things to look for as far as early or late production rifles are concerned is barrel lugs vs. pinned in barrels and milled trigger group vs. stamped steel.

None of these features make the rifle good or bad both shoot the same and just as accurately,they just give you some idea of when the rifle was probably made which I would guess without looking at it to be between 1963 and 1966.

You can find some other info on your rifle here.
http://yooperj.com/SKS.htm