It’s a 2009 Beta Mag ($300), and I lubed it before ever using with graphite from the provided kit/carrying case, and it fed like a hose. Cleaned it every other mag load thru. Never a jam for me, in the 5x I used it.
It was heavy as an anvil, full load of ammo, so I switched to the Surefire 60rnd mags from Brownells:
http://www.surefire.com/tactical-equipment/high-capacity-magazines/mag5-60.html
What a sweet mag.
Yeah, I thought it would be very heavy.
Bought the Surefire 60 last panic buy before we moved to VA. Embarrassed how much I paid for it. Haven’t even tried it yet. Ranges near McLean are farther away than Bethesda.
Have you tried the Surefire 60 round mag yet? On Surefine’s website they were listed at $159.00, are they cheaper at Brownels?