Core derlin bolt with venturi drilled out
polished striker and trigger group
14" SP progressive
derlin so it doesnt f@#$ up your reciever when you run out of oil
VENTURI kills efficiency
I got one of these for ~$10 because i was tired of constantly lubing my stock bolt to prevent heavy scratching. The first thing i noticed was it had a milled air port with a cure shape to it the air port was also much larger than the port on my stock bolt. Before i even used this thing i put it in the drill press and used a 3/8" bit to drill out the venturi i probably could of drilled it out farther but i was afraid that i would weaken it too much so i left it at 3/8"
Only drilling it to 3/8 left little ridges inside. which should help straiten the air flow so it hits the ball more evenly. Because of the higher flow it will make the gun more efficient and add 100 shots to your shot count. Now i can get over a case worth of paint out of one 20oz tank.
I highly recommend this bolt to anyone especially if its been drilled out like mine. I give it a 9 because it requires machining to make it perfect.