Among my semiautos that fire .308, I have lots of loose ammo, and no way to bulk load for the HK91, DPMS SASS, or M1A, although I have the LULA for M14 magazines. While buying other stuff from Cheaper Than Dirt, I decided to gamble $20 on a "universal" loader for this caliber.
This chicom product uses proprietary ten-round stripper clips to hold the ammo, and a guide that sits on top of the magazine. Slide in a clip, crunch down with the T handle, and, if lucky, ten rounds are nicely seated. A vey strong magnet at the top the the T then pulls out the empty stripper clip. The darn thing actually works as advertised for all three types of magazines.
I have 60 stripper clips (50 cents apiece), and it's a real PITA to load the loose rounds onto them. (Oh, and GI 5-round stripper clips won't work.) But once that's done, I have an "intermediate product" that can quickly load any of the three different types of magazines I use. Between a thousand rounds of loose ammo, and a few thousand more that come in cardboard boxes of 20, I'll be refilling these stripper clips about as fast as I empty them, rather than face all those individual rounds.
Another way to handle 7.62mm NATO ammo is to put it into 50-round drums for the HK91/G3. The biggest problem is that these drums are almost extinct, and can cost over $4K if they can be found at all. American ingenuity, and CNC machining, has brought us a $400 clone, currently on sale for $260. This is pretty steep, but close to the price of the Beta Cmag for the M16.
Here it is, along with a new-style GI first aid pouch, which I found out makes a good mag pouch for the beast.
It's machined from solid aluminum, with the winding wheel on the front being the major plastic piece. When taken apart for cleaning/lube (only dry powder, I'm using powdered moly), we see the pair of scrolls that keep the rounds in a spiral.
The spring mechanism is in the front, under the winding wheel, and the instructions warn of vey series consequences if you mess with it.
The magazine seems deceptively easy to load. With spring tension low, the first few rounds go in easily as you wind up just enough of the spring to let the next round slip on top of the previous one. The loading gets tougher with the more rounds you have loaded, because the spring is now almost completely compressed. Holding the magazine still also becomes a problem as the spring pressure increases. The last few rounds are real bears.
Unloading the magazine (rather than shooting off the contents) is a reverse of the loading chore, with another "gotcha" to worry about.
You start by putting even more tension on the winding spring, in order to release pressure on the top round. It should just fall out with a bit of a push. But you're holding back the other 49, and you have to slowly release tension so that one round at a time falls out.
The scrolls are deep enough to hold the cartridge up to the shoulder, and a bit of the base. That leaves plenty of free space for rounds to fall out of the spiral if they have no tension on them.
If you're lucky, you can rattle the round back into position while restoring the tension. Unlucky, and you have to risk taking the magazine apart with some rounds still in the spiral, and some loose.
In my case, it happened on the last few rounds, so there was no real spring tension to worry about when I took it apart and just removed the offenders.
The bad news is that this type of magazine is tricksey to load and unload. The good news is, you can do a lot of shooting once you load it.
Here's my setup for medium-range sod poodle control. With a loaded drum weighing 5 pounds (almost the same exact weight as the 5.56mm Cmag double drum holding 100 rounds), this is the kind of 25-pound setup that invites you to pitch a beach umbrella over it, open a cold drink, and just wait for targets.
The manufacturer also promises future versions for M14, M16, and AR10 magazine configurations. So start saving, and start on those wrist exercises.