The Lancer L5 initially did not inspire much confidence. I had just got done handling a Magpul Pmag and felt that the body of the L5 was nowhere near as rigid as the Pmag. The feed lips of the L5 are steel pieces molded into the plastic body. I was afraid that this would not last long. With these points in mind I looked the rest of the magazine over and was pleased at the design.
The L5 has several features that make it more desirable than the old USGI magazines. It is made from a translucent polymer with a rubber coated polymer base plate. This affords a bit of cushion when the magazine is dropped from the magwell on a reload. It is marked on the side at 20 and 30 rounds allowing for you to see how many rounds are in your magazine without removing it from the weapon.
The magazine follower is of an "anti-tilt" design. The original sample that we have has a follower that will allow for a bit of tilt, however this never caused a problem when loading or feeding.
The L5 body has a heavy ridge where the magazine well of a M4 would terminate. This is apparently to prevent the magazine from skipping past the magazine catch, although I have never actually had or seen this happen. This could prevent this magazine from being used on some of the newer "stylish" AR lowers with non-standard magazine wells.
I have been using this magazine during our rifle training days as my primary on each string of fire. This exposed the L5 to the maximum number of drops and reload cycles. I have been "experimenting" with the L5 for a year now. Running it in my suppressed M4 has resulted in exactly ZERO malfunctions. Since this magazine was run in a suppressed platform it received a large amount of carbon blown down from the action. I did not clean the L5 for the duration of my testing and this did not affect reliability.
I regret that I did not keep a round count during my testing. It was during actual training, not just target shooting. As such it's a little difficult to keep track of the number of rounds fired and loaded.
I found that the Lancer L5 worked exactly as advertised.
I did not bother running over a loaded magazine in my truck or any other nonsense you see when folks are "testing" these magazines. I have never had a need to let a Humvee run over my magazines when I was on active duty and I sure don't see a need to use them as paving bricks now. I have confidence that these magazines are at least as durable as my USGI aluminum magazines.
When I initially began testing these magazines I was using a thigh mounted MOLLE platform with magazine shingles. The Lancer L5 fit perfectly in these pouches. I recently upgraded to a new Protech entry vest. I mounted two ITW "FASTmag" carriers on the chest. The L5 would not fit securely in this carrier. It would bottom out just like the USGI magazines, but it took hardly any pressure at all to remove. I was afraid that and bouncing at all would dislodge a loaded magazine. I was quite certain that if I had to go prone the L5 would be in the dirt. This is not a failing in the magazine, just something to be aware of. If you run anything other than a standard GI or Shingle type pouch you may have problems. I also noticed that if I used the Protech double M4 and Double pistol pouch that came with my new vest, the L5 was extremely hard to load into the pouch. Removal was possible, but with increased force.
Overall I am very satisfied with the L5's performance. After year of hard use in a my suppressed rifle the top of the magazine is no longer translucent. It's covered with carbon. However the lower 2/3rds of the magazine is still clear and I can still use the round count markers. I would have no problem recommending their use at the range or on the street. The only caveat is to make sure they fit your magazine carrier before you buy a boatload of them.