The Rimrock and Alpine/Timberline actions were designed by Gary Amatrudo and Jim Borden. The actions were designed to achieve better accuracy and precision inBenchrest, Varmint and Hunting Rifles. The Alpine and Timberline actions are made specifically to be able to be used in stocks inletted for Remington 700 Actions. The Rimrock SSR and LSR actions are also made to be used in stocks inletted for Remington 700 Actions. The difference between the Rimrock LSR and SSR actions and the Alpine and Timberline actions is that the Rimrock actions feature the "Borden Bumps". The already tight bolt to receiver fit on the Alpine and Timberline actions (<.002 inch) make them tighter than the competition and are ideal for precision hunting rifles. These actions are made to specifications and tolerances that are unmatched in any other Remington "clone" action on the market.