Thanks prodigy, I literally don't have a penny to spend on anything at the moment, but have plenty of bits and bobs to try and mod it.
JM360, I feel the problem with your method is that the piece of plastic, if it came loose, which it has a very good chance of doing with all of the vibrations the gun undergoes, it can fall out of the valve. The 7mm bushing has the advantage of not beingable to fall out of the valve and isn't attached to anything.