So I have about 500 rounds thru new 30S. no misfeeds from either of its 10 round magazines. I now can confirm just about every other bullet misfeeds when using my stock 21 13 round mag, and worse, misfeeds 2 of every 3 from my other 2 glock brand 21 mags with +2 bases. all these 21 model mags feed fine in the 21. misfeed is usually bullet nose partially in barrel but back of it still in mag - so it sits at around 30 degree angle and slide does not close fully. any ideas why? should I send back to Glock for repair?