A dealer at a local show has had what is alledgedly "tungsten cored" SS109.  It is supposed to be British mfgr.

Is anyone familiar with this ammo, or is he smokin crack??

Thanks,
Mike

its run o the mill ss109 little underpowered tough. no trouble in my bushy m4

He's smoking crack.

SS109 (M855 in the US) is steel penetrator and a lead core.  It is NOT considered to be AP.

The only tungsten cored 5.56 is M995, which even the military rarely sees.  It's too expensive to produce and is considered to be specialty ammunition.  This is what many dealers try to pretend their M855 is.

Well...there's also some "green" M855 that has a steel penetrator and a tungsten/tin core that is bonded with nylon.  It's also not cheap, but it's been designed to be more "environmentally friendly" than lead cored ammo.

"M4-Shooter" is right.  British 5.56 ammo is lightly loaded to cycle better in the doorstop of a weapon they have (SA-80).