Just bought a 10 rnd mag for my NORINCO SKS, & it doesn't seem to fit, I put it next to my 30rd mag that does fit, they're both the same lenght, but there seems to be on the fore front of the mag of the 10 rnder, a lil' bit more metal (about an 8th" or 16th") that's not allowing it to "seat" from front to rear...should I file down that lil' bit to make it fit? or just sell this one (hard to find) & get a Chinese 10 rnd magazine? Are there differences between Euro SKS mags & Chinese SKS mags? (apparently so)

Thanks for your help...