ELEY BR-50 Benchrest Ammunition

I was recently given a sealed packet of BR 50 labelled 22 Rimfire ammunition, made by ELEY.

I an seeking information on the originator of the BR 50 discipline, who I believe was an American, Larry …?

I am also seeking to confirm whether this ammunition was different to other ELEY ammunition of the time or was merely their run-of-the-mill target ammo with a BR 50 label stuck on.

Many thanks.

A quick google search, benchrest 50, yielded a couple of sites: