I've already loading this to 60 rounds before. Contrary to what you might read, the physical effort needed actually isn't that hard.

But I unloaded it recently and then went to load the rounds back in, and now it stops at 48 rounds.

Before everyone tells me to just put some elbow grease into the lever, the lever isn't the problem. The problem is that the top round doesn't compress far enough to make room for another round regardless of how many times I ratchet the lever. It's not hard to push the lever all the way, but the 48th round at the top doesn't actually move down when I do it. It feels like pressing down on the 30th round of a normal 30-rnd pmag, there's a sudden hard stop.

If it weren't for the fact that the round doesn't actually feel that hard to press down on before suddenly meeting a hard stop, or for the fact that I've loaded it to a full 60 rounds without much effort before, I'd be inclined to tell myself that I just have baby hands and need to put some elbow grease into it.

But the abrupt change from not-hard-at-all for the 48th round to full-stop when trying to do 49 makes it seem to me like there's something getting caught on something else inside the drum.

Or if you don't know what's wrong, feel free to chime in with baby hands jokes


Update:
Figured out how to fix the problem. Description in the third reply of the thread.

I had mine jam at round 50.  I ratcheted the lever and shook it side to side and up and down, lightly banged the back on a table top.  Was able to get 58 in the first time loading.

ETA: it was way harder and time consuming than I was expecting.  Having uninvited company would not be the time to try to load that sucker.

The solution is... contact Magpul. Seriously though, it might be interesting to disassemble it following the instructions they include with the drum to see if there some kind of visible obstruction or damage. However, with the possibility of coming restrictions, I would call Magpul, and if they don’t have a quick solution over the phone, start the exchange process immediately.

Update:
I solved the problem.

If you're having the same problem I was, don't press down on the top round at the same time that you crank the lever. Crank the lever over first without touching the top round, then push the top round down after you've cranked the lever over. The top round will depress if you wait until the lever is cranked over before you start pressing down on the top round.

I've found that using a StripLula makes it much easier to load the D-60.

I wholeheartedly agree with the striplula comment.  I lube my d60 every 500 rounds or so.

Yup. Attach Striplula, add stripper clip and keep downward pressure on the ‘lula “plunger” while ratcheting the D-60 lever. Towards the end, rnd 50+, you may have to ratchet a couple times per round but it’s fast and easy.