Hi,new guy here and I found you on account of this thread,got myself one of these Suomi's:
Mine's in the 800 number range,came with a sling and one stick mag,no drum.
Upon my first shoot with it I had a jam,the same as the rest of you, and thought nothing of it,after a few I decided to look into what was up and maybe fix it-why I felt this was because I noticed the bolt felt "sticky" so I commenced to playing with the gun all-night-long (normal for me with a new friend
)
After a few hundred times yanking the bolt open and closed I surmised the thing was hanging up on account of the bolt,if I eased it forward it would just stop about half way,sometimes it would stop if I yanked the bolt all the way back and let go~not good!
I scratched my head and started to look online at pics of the Suomi in it's original full-auto guise,and I noted the bolt was silver,not greyish-black~hmmmmmmm
A trip to brpguns.com and a peek at the bolts there confirmed it:the original finish was silver,not grey soooooo-they parked it! damn! if it's too thick it can hang up the bolt,right?
I grabbed my dremel,a polishing wheel and some polishing paste and went at it.
I didn't polish off all the finish just enough that the bolt felt smooth,it's working fine now and I'll continue to test it,if it hangs up anymore I'm just going to get some reg polish paste and polish it
silver again!
So try the bolt if it jams and see if it sticks any,if it does try polishing it and see what happens,for me that's working so far.