Since the surefire 60 round mags have came out a few years ago I have been doing some long term testing of them. They seem to have a shady reputation for reliability in some corners while others deem them fine. I have written about them a few times already. I tested them for reliability and durability, as well as talking about how the changed the handling of a carbine and perceived weight. Last year I wrote about how I left two of the 60s fully loaded for a a hair under 2 years, then fired them with no problems.
I continued that test and had another surefire 60 round mag fully loaded for a hair over 3 years. I had planned on firing it and writing about it, when a friend brought over a full auto lower. It was a great chance to test the mag since full auto is more strain on everything.
I slapped my Colt H3 buffer in the lower and my Colt 6940 upper on the dealer sample lower and fired the surefire mag in burst.
As can be seen in the video. I worked perfect. I followed that up with a few more times of using it in longer bursts with no problems. The Surefire magazines may be hit and miss and have a certain rep online. But I have had no problems with my three and long term testing and efforts to get one to fail without completely abusing it, have shown them to be reliable. I will continue long term testing with updates since the mag is still is in doubt as a useful piece of gear. I have to say that I still have confidence in the ones I have been testing and would use them without worry.