VM-68 questions - odd Smart Parts barrel milling and aftermarket bolts?

[Chuck E Ducky]

I used one of thoes regs to get a Hammer7 to velocity on HPA it shot great.

[The Inflicted]

I used one of thoes regs to get a Hammer7 to velocity on HPA it shot great.

I'm surprised. I didn't know those had such velocity problems. Were you not able to respring it?

[Chuck E Ducky]

The bottom half of the bolt is flat so it don’t clip on the mags. So it’s got tons of blow by. You can gain 45-50 FPS by filling the bolt with JBWeld. I was Dye magwell modifying them at the time.