So my buddy blessed me with an sks he's had in his safe forever. Said he never shot it, gave $80 for years ago, and thought i'd like to have it. I opened the case whe he handed it to me, and there sits this brand new, unfired Norinco, covered and filled with cosmoline! Took me 2 hours to clean it up. Now, i've never owned an sk before, so looking for a little help. Tried a Tapco 20 rd mag in it. Fit is too tight, and there is no bolt hold open with the mag out. You can't insert the mag with the bolt closed, so it takes at least 3 hands to install. Also I can't speed load the Tapco with stripper clips. Won't accept more than 7rd's max. The stock mag is pretty tough to strip into too. I want to attribute this to being brand new and requireing some break in, but not sure. Any thoughts?