With 'low pressure' (LP) being the latest fad these days the question has been raised as to whether the internal expansion chamber (EC) mod really acts as a EC or is it a LPC.

For that chamber to work as a low pressure chamber (LPC) you have to have a few things done first. Just because it's there doesn't mean it will magically lower the operating pressure of a stock/near stock VM. If the air passages and/or valve are unmodified and the stock hammer and/or springs are used the VM will still require 700-ish PSI to operate. Once you tune the VM then, yes, it will act more like a LPC.

LPCs don't lower operating pressure by themselves. With a properly tuned VM (or any gun for that matter) they can assist in lowering operating pressure. The LPCs you see on Spyders/Cockers/Angels are mostly there just for looks. They have little to no effect on performance.

LP will:

• Make your marker quieter
• Make your marker a little easier on paint
• Make your marker more stable in velocity
• Make your marker more expensive
• Make your marker more complex

LP can:

• Make your marker more efficient
• Make your marker easier on internal parts
• Make your marker less temprature sensetive

LP can not:

• Make your marker shoot farther
• Make your marker more accurate
• Make your marker shoot "flatter"

That being said, here's a good way to go about making your VM run at a little lower pressure:

1) High flow valve w/tuned spring
2) Drilled out transfer port
3) High flow bolt
4) Internal expansion chamber mod w/drilled out port to valve chamber
5) A good LP regulator

Now, I will say that I've seen blowback markers like the VM that were so quiet I had to listen distinctly for the sound of the bolt. If that's your thing go for it.