New CZ 83 new member questions

[puppyface]

Hello: received my surplus 83 from SOG international today.  268 plus 10 for handpicked.  The weapon arrived in good condition: the bluing is worn but not scratched or pitted. Sights are dead on, good accuracy.  The trigger pull is excellent.  One problem: I shot 100 rounds today using Winchester white box fmj and some PMC fmj.  The weapon functioned well until the  last one or two rounds and then a FTF occurred.  I stripped and cleaned the mag and gun completely.  I tried loading only a few rounds  and the same thing happened.  It was always the last one or two rounds.  My guess is that the mag. spring is worn, but I am not sure.  Any suggestions?  Thank you in advance.

[SMSgt]

Wolff Mag springs. Might as well order the recoil spring while you're at it. No telling how much wear and tear is on them.

[puppyface]

I ordered a factory mag yesterday from Midway.  I want to try a new mag and check to see if my feed lips are in spec. I wasn't sure that Wolf had springs for this weapon, I will ordered both and try them out.  Besides ammo, I cannot come up with any other reason for this.

[puppyface]

I don't see mag springs on Wolfs site.  Should I stay with stock pound recoil 
spring ?

[puppyface]

In case anyone is having similar issues: I received a new factory mag from Midway ran a couple hundred rounds through the 83 including Wolf steel case, no FTF's.  Nice gun. The double action pull unbelievable. Can decide weather to refinish it or leave it 

[SMSgt]

Have you broken down the guilty mag and cleaned it? They collect gunk badly. Might be all it needs.

[puppyface]

Yes, I stripped it down real good.  I just noticed yesterday, i shot some tula steel case just for the heck of it, and I got some FTF with the new mag.  So I immediately ordered a new recoil spring from Midway.  I am hoping next shooting session my problems will be solved.