ehem..ehem..., doc, those were heavily modified mec-gar mag followers. Combination of dremel, soldering iron and sand paper. ;f
A friend also uses the same mecgar tubes and bayang pads. But he uses wolff springs and the arredondo followers. His BP is thinner pero napagkasya nya rin 19.
Mas mura mecgars sa Twin Pines lalo na kung gun show.