09-25-2019, 08:01 PM
Mad Charlie Wrote:The pin might make it a little hard to lap the extension...
Most uppers are cast. There are some "billet" uppers. I have no experience with billet, all four of my uppers have needed lapping.
Thanks for the reply Mad Charlie.
I understand the index pin could hinder this process. I am just trying to justify lapping using other's experience(s).

