I think in the early day of AR, the stock was designed to accept a sling (my first AR accepts a sling.)

But as ARs get fancier, with things like free floating hand guards, they seem to have forgot about the sling.

I have one free floating had guard with a built in QD connection, but the stock I have on it doesn't support QD.

I have another AR where the stock supports QD, but the handguard does not.

Have the gun manufacturers just given up and said this is M-Lock, or Q-Lock, and you need to find an adapter?

How hard would it be for them to build a QD adapter into the handguard, and document it, as a feature?!