[Ben3721]

I agree those springs will shatter. Also you need to check your math because with the pasts list you have it calculates to 83 rounds per second. Too high to run without burning out or pme.

The 30k Motor would be better.

Also a dsg doesn't pull a spring back all the way, meaning you'll need a higher rated spring such as a m150 or even m180. With that part list and motor the piston will likely remain back from pme entirely.

But with that stress you need to make sure you have a metal cylinder head, perfect air seal, aoe, radius the shell, and padding on the cylinder head as well.

It's good that you made a post. Hope all the info helps ya with the build.

 

[Ben3721]

The marks inside a barrel that look like ripples is not from machining. They use a floating center rod and press in the outside to the rod to form the bore. If it has worn out edges or is imperfect it will cause those ripples.

I may be wrong but last I checked that is how they make barrels in general. At least stainless ones.

Also the issue with coated barrels is the fact lube filled with hardened steel dust from the gearbox gets into the lube and then thrown into the barrel, which is then crushed and dragged down the bore when shot. Most this wear is right under the barrel window. For a brass a quick polish does the trick, for stainless lapping is an option, but aluminum or coated brass, not so much.

Ive also seen barrels peel inside.