Gas Piston - question about the piston...

[Nahway]

I have a Bushmaster gas piston AR15... (Image not mine, just looking to illustrate a question)
http://img838.imageshack.us/img838/9742/completeparts.jpg

Can anyone explain why the piston is double sided? One side has larger/more holes than the other side.

The rifle functions with either side inserted towards the operating rod. What's the purpose of this 'double ended' piston?

Also, I was wondering what the benifit is, (if any) of not having a spring inside the piston system.

All help/insight is appreciated.

[MistWolf]

It would be best to contact Bushmaster with your questions as they should have first hand knowledge as to why it was designed that way.

You will find most folks on this site prefer the simpler, original AR piston system

[Kyohte]

Because the employees couldn't figure out which side to drill, so they did them both.

If the holes are different sizes, my guess is that it's to regulate that gas (more or less depending on the hole size).

As far as lack of a spring in the piston system, it's just one less thing to go wrong. An AK lacks a spring on the piston, as does the FN SCAR.

[ThreeLeafPayback]

Gas piston w/2 grooves forward is "normal" gas position.
Flip it around for "supressed" operation.

[Failure2Stop]

Ask Bushmaster