Recently I purchased a Bushmaster ACR chambered in 6.8 Remington SPC (Review pending) and was curious as to whether one could use a 5.56 GI or PMAG for the 6.8. I did research online and found a few articles that got into the technical aspect of the difference between the two rounds and magazines. Much of this was understandable but lacked simplicity. Many times, I look for the simple answer of yes or no, and the simple answer is no.
Being the owner of an AR-15 with more 30 magazines than I could actually use, I wanted to test the feasibility of loading 6.8 into my 5.56 mags. I took some 6.8 rounds and began loading them into a standard GI issue style 30 round magazine first. This magazine did accept the rounds with relative ease until I got closer to having 10 rounds loaded. As I loaded rounds into the magazine, I noticed it becoming more difficult after the eighth round and once I hit ten, I had to use considerable force to get one more round in.
I decided that this was my conclusive evidence that I was on a fool’s errand to consider the 5.56 magazines as interchangeable. I began to unload the magazine, having difficulty at first unloading was frustrating. Once I got back around the eighth round it was easier to unload, so I guess you could consider using a 30 round 5.56 magazine if you only wanted to load eight rounds. My experiment helped me understand what I had read in other articles by puttingthis into personal experience.
Having discovered the error in my thinking of interchangeability, I am not discouraged from keeping my new 6.8 as a primary platform. I have high hopes of increased availability of ammo and accessories for the 6.8 as the U.S. Army has stated it will adopt the 6.8 as a primary round for light machine guns and future M-4s. This dedication by the Army should prove to increase the supply of 6.8 ammo and possible increase the popularity of firearms chambered in 6.8.
Copyright B. Jarret 2019