i was looking at some magazines for sale and saw a surefire mag for a saiga 7.62 priced around $45. then i saw a pro mag priced for $24. i was wondering what the difference was between them and if the pro mags are good to buy even though they're half the price of the others. do the pro mags cause jams or something else to reflect the price difference? they were the same rd count. thanks, i need some guidence.