The Mounting Block provides an option to mount a Rail ABR to a flat recoil plate. It was designed for the Eliseo recoil plate but it can easily be modified for other uses - Tubb 2000 for example. When used on an Eliseo recoil plate it will allow the Long dowel Rail Mounted ABR to be used. The bracket hole should slide over the roll pin and use the same 1/4-20 flat head bolt for mounting. It is a standard 'Picatinny Rail' on the bottom. The modified bracket is designed to the fit into the lower section of the FX M3 Impact and FX Maverick ( with minor modifications) and mounting. Non-Affiliation Disclaimer. We are not affiliated, associated, authorized, endorsed by, or in any way officially connected with the Eliseo Rifles.