I found the 10 round Ciener mag can be increased to 14 rounds quite easily.   Here's how you do it:  Slide off the floorplate on a 10 round mag and remove the pin/spring guide from the mag body.   Replace the floorplate and now you can load 14 rounds in a 10 round mag.  Squeeze the bottom of the mag body so the floorplate is retained by friction.  Reliability remains the same - no binding whatsoever.  

The only issue: the 14 round magazine has to be inserted with the bolt held to the rear.  But, f you load 13 rounds, the mag can be inserted with the bolt forward.  

I haven't tried it with a 30 round mag, but I'm guessing there would be binding with the higher capacity magazine due to the length of the spring.  

Dan