Polyurethane spacers work well, and I have never seen or heard of any problems with them breaking down.
A person could use aluminum and to make spacers, but it is not worth the time/effort as poly spacer cost about $35 a pair.
According to the National Shooting Sports Foundation, AR-15 sporting rifles account for nearly 20% of all U.S. firearms sales.
Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......
Originally Posted by Ronald W. Reagan: Government is not the solution to our problem; Government is the problem.