Not sure what about a Larue mount is fragile, especially as compared to the sling swivel mount but…
If you already have a rail system on the gun there may be no sling swivel, or provision for same, leaving the rail as the best attachment method.
Rob I could have sworn the Vltor was released?
I think it is, I just haven’t had a need for one/them, so my only exposure is still via their booth.