James,
[Regarding Pat’s recent product review,] as a licensed Class III dealer, I have extensive experience using the X Products 50 round drum for the HK91/G3 under full auto fire. My G3s, HK91s and even semi-auto PTR-91s eat NATO standard ammo flawlessly from them. I also have used the M14 version successfully though I don’t have as much time with that rifle. I heartily suggest their use. I have no monetary interest in their company. I and my company own and use dozens of them.
I also strongly suggest the PTR-91 platform for standardization in any survival group. As long as you use NATO spec ammo and good mags, they function flawlessly. Service is easy, only takes a few specialized tools and mags are quite cheap. they are a great value versus the classic collectors pre-ban HK-91.
Thanks for what you do. – B.F.