Originally Posted by Azathoth
You mentioned you got a preproduction valve. The one I ordered was VERY well machined no rough edges etc. I've installed because i needed a extra valve for the other gun and wanted to try something from ARS. The Blow back 'feels' crisper but that is very subjective. There was little to no FPS difference that I wouldn't just chalk up to temperature variance and chrono error.
I don't know at what stage of production this valve was when I received it. I got it around September of last year, so if anybody can correlate that to the production schedule, then please update me.
While the edges are rougher than what I'm use to, by no means is it like a sawtooth. It has machining marks on it. While not major in size, the ridges it presents may cause enough turbulence to affect flow, especially since they are on the direct face that the gas will contact as it releases from the magazine. I'm just used to valves that don't have these marks. Either they were machined with a slower feed, sharper tools, or were honed afterwards. Whatever the case, a test unit should be very similar and/or same to the final product, otherwise what's the point in sending out something so rough if you might experience a scathing review of a product that hasn't even hit market yet? But for what it's worth, what I have in front of me looks just like the picture shown in the OP.
I could very well chalk up the differences to variances presented by gas systems. I wouldn't chalk it up to temperature vairance and chrono error, as the chrono I have has always been very accurate. It's very consistent with AEG's. As for temperature, I did all these tests within a time span of 30 minutes, so I don't think temperature could have changed that much.
There are also variances that can be attributed to how the gas was filled, how hard it was pressed in to the valve, and thus, specifically how much gas was in the magazine.
If it were to be made in to a very controlled test, I'd have a regulated HPA direct line hooked in to the magazine to further control any variances presented there. Unfortunately, I don't have such a setup.
By no means should any of these tests be an end all be all conclusion when it comes to gas. There are just too many variances. But the main point of my response review was to prove that there was just no way an ARS valve can provide a 40fps increase over a stock valve, which is where a lot of the confusion was laying.