KA-PP-19
http://www.kingarms.com/product_detail.php?id=3005
MIM Steel stopper for King Arms Python 357 Series
Product information:
For King Arms Python 357 Series (KA-PG-01 / KA-PG-04),
For better durability
Reinforced parts for PG-01-18-A02
Specification:
Size  | L:42 W:5 H:6mm  | 
Weight  | 0.1 g  | 
Main Material  | MIM Steel  | 
Major Color  | Black  |