Thanks about the stock. I got the idea and help from THEO, he modified an ACE stock for his LR-300 and then told everybody else how to do it! Great guy! hat is what I love about the LR-300, NO BUTTSTOCK SPRING & nice fold away buttstock.
The brace on the front of the rail:
[img]http://www.imagestation.com/picture/sraid67/pd52d828bbb45cf9df173341329914bb1/fbd31dbc.jpg[/img]
[img]http://www.imagestation.com/picture/sraid67/p5af895cbd0bae1990257448a639ff18e/fbd31dbe.jpg[/img]
Edited to add: There is a small screw hole on the front of the rail to hold a "bush breaker" to keep objects from getting under the rail & handguard. You should be able to modify something to give the rail rigidity. I had to use aluminum, as the brace rides atop a sheetmetal covering for the op-rod spring (in lieu of buttstock spring) and get very hot, so plastic would not be feasible.
Maybe on an AR-15, one could use some rigid plastic similar to handguard material to make a brace with...?