It’s been ages since Chris Costa and Travis Haley made names for themselves with Magpul Dynamics. While at least one of their kinaesthetic products – the Magpul AFG-2 – has become a modern classic, time hasn’t been so kind to the BAD Lever; now deeply unfashionable in shooting circles and rarely seen in reference pics.
While some still consider it a useful addition, the BAD Lever is now something of an anachronism. As such it’s become part of the toolkit for dating UKSF reference pics with the idea that if a BAD Lever is present, the pic probably isn’t particularly current.
Designed to considerably improve the speed and efficiency of the AR15/M16 bolt catch, the B.A.D. (Battery Assist Device) Lever quickly addresses reloading and malfunction clearance shortcomings of AR15/M16 platforms by extending a paddle to the right side of the weapon, allowing manipulation of the bolt stop from the fire control / ready position with the right-hand trigger finger.Magpul BAD Lever product description (source: Magpul)
In terms of UKSF BAD Lever use post-L119A1, SAS trooper turned evangelist Kevin Charles-Thompson has posted a couple of excellent pics on his Instagram account.
I’d guess these are older pics because of the BAD Lever, and because another pic of his L119A2 which doesn’t appear to exhibit a BAD Lever, does show newer accessories – the Aimpoint T2 with spacer and LRP mount, and 3XMAG-1.