Anyone have info on the British Army using their L86 Light Support weapons as Designated Marksman rifles (as they did not make a good LMG)...

The barrel is already free-floated, right?

That wouldn't surprise me. Part of the reason they introduced the Minimi to serve alongside (Not instead of) the L86 was that the British shooters found the weapon to be so accurate that they were using it like a fully-automatic sniper rifle instead of the suppression weapon it was supposed to be.

NTM

With a 25" barrel you think they are getting pretty zippy velocity out of the 5.56. The SUSAT optic is probably limiting the rifle in this role though.

I did some googling and found this:

The L86 is now being supplemented by the FN Minimi, a belt-fed weapon capable of longer bursts of fire. The long barrel results in a particularly high muzzle velocity for an assault rifle. Combined with the free-floating nature of the heavy barrel and the optical performance of the SUSAT, this gives the weapon excellent accuracy. This has lead to it being 'rebranded' as a DMR (Designated Marksman Rifle) with the introduction of the FN Minimi as a replacement light support weapon.

and this:

Russian RPK gunners who were equipped with scopes commented that they could now shoot as accurately as snipers. It may be in some units the DM is also a SAW gunner.