What are the options for contemporary belt fed rifle designs?

The MCR is just the old vaporware then unreliable Shrike with a few other stops along the way and company name changes. Purportedly works, but I have difficulty trusting them.

As far as belt fed uppers for ARs... not a lot of them. Others I know are the XMG, an MG34 design and in 308 or 8 mm but it had some legal oddities, and the RPPR a .22. yes, a bet fed .22.

Got to poke at a semi-auto Minimi (M249) and it's pretty nice, no hacked up stuff from being semi-auto. FN knows their game, so it probably works great also. A bit inconvenient to use as no bolt lock so their official policy is this thing you stuff in the mag well to hold the bolt back to load and stuff (remember, open bolt = MG to the ATF).

https://fnamerica.com/products/rifles/fn-m249s/

Heavy, expensive, but reliable and the closest you'll get to a new belt-fed machine gun without being a SOT.

There's ARES. I think they're the ones who originally built Belt fed AR-15 uppers.I may be wrong though.

Edit: I see ARES Defense changes their name to Fightlite and is currently marketing the MCR upper. It's not a topic I frequently keep abreast of.

Basically, the design based off the AR. The rest of them are based on MG's of years gone by.

The Minimi is newer than the AR15 by decades.

The Shrike/MCR is "based on" the AR as loosely as it is possible to be:

Piston not gas pressure operated.

Piston is on The Side. See that little nub on the bolt carrier?

I guess it probably uses standard bolts and buffers but that's it.

If I had Transferrable money I'd build up a heavy barrel, good upper receiver setup with an adjustable gas block and run C mags (or something) through the magwell, not fuss with belts at all. Take the time you would be linking on your linking machine, to PM the mags and it'll run. Don't let me spoil anyone's fun, but belts are a pain, and a lot of extra cost at every level of operation.

In my avatar picture the belt came unlinked so I draped it over my shoulder for the picture. You have to practice for stuff like that.