I am thinking of making the adjustable valve spring in my RAW. May be at some future time. Like the one below made by a Rapid user.
Here is the latest on the newer RAW's. Some of this you probably know. This info came directly from Martin so it's accurate. The external size of the receivers is the same as the old except at the breech end it has been opened up to accept thicker magazines to accept longer projectiles. The plenum along with most of the insides have been made larger. That's the reason the reg. is set at 130-135bar for the new builds. As far as the size of the plenums he said that he never has tried to measure them. He most likely made the new plenum as big as he could and still be safe. Buying any of the new parts would have to go through Air Force, so good luck there. They wouldn't even tell me what kind of o-rings are used in the regulator. When asked there answer was ''we don't give out that information''. I don't think they knew anyway. Simply put the newer guns have the capability of more power than the older guns without making any modifications.
With all the talk about getting more power not much has been said about doing anything to the transfer port. Is it already perfect? I haven't taken mine out to see what it looks like. Good gains in power can be made with some guns by opening it up.
I understand that now RAW uses the same action that they used for .357 caliber. .357 caliber needed a thicker magazine for longer projectile. Now they use .357 action and make the magazine of .25 just thicker to fit in the action. Keeping the same action for all guns saves manufacturing cost.
I understand that by enlarging the internal dimensions of the same block cannot give as high power as 25cc external plenum can provide.
In the past the tuners of Rapid have also enlarged the inner dimensions of Rapid but I understand that the old RAW was really good being a bit overbuilt.
Now the niche market product is becoming a mass production item. Business is always guided by innovations and compromises.
Finally the transfer port is perfect and you need external plenum and high efficiency valve etc.
I think you can still send your RAW to Martin for customized work on it.
Regards,
M. Bhaur