Edgun R3M Short: how to find the perfect synchronicity between the reg and HST

[sen]

Hi everyone.
I own an Edgun Matador R3M Short .25 cal. I am very happy with this gun - accurate, dependable and very efficient and comparatively simple design.
I also bought the HUMA power plenum kit in order to try and get better results out of the gun. Now, I am very happy with the HUMA reg, but perhaps due to the shorter barrel of the Short version, I cannot get it to shoot the JSB Exact King Heavies with more than 800 fps (with the reg set at the recommended 140 bar). As advised by Brian from Edgun West, I checked several things - how far the valve stem is protruding, the diameter of the porthole, etc. Everything with the gun is fine, plus there was a delay in the delivery and I spoke to Ed, he personally assured me that the gun had been tested before it was shipped to me. There could be another reason - some guys tell me that the sticker on the HUMA reg does not correspond to the actual output pressure, and quite frankly, I suspect this is the problem, but I do not own a HUMA reg tester.
Now to get to the point - a lot of people keep telling me I need to find the perfect sync between the HST and the reg setting. How do I do that?? Do I need to start randomly testing different reg settings with different hammer spring settings? Like trial and error? Because to me it seems that there are a lot of possible combinations between the two and I really can't imagine stripping down the rifle dozens of times, over and over again - it will definitely lead to some damage and soon. Are there any guidelines? Or perhaps someone has managed to achieve this coveted sync with this very Edgun model or one similar to it?

 

[zx10wall]

You didn’t mention the hammer weight. The R3s need a hammer weight to get the fps of the 34s up there. The lightish factory hammer doesn’t create enough dwell. The R5s don’t need the extra hammer weight. 

Once you get the proper components in place, you should probably set the huma on 145 bar and test. Find the first peak fps with the reg setting by dialing in more hammer spring tension. From there the harmony usually occurs at 10 to 15 fps less than peak.

 

[sen]

zx10wall, thanks for your reply. I tried the hammer weight - it gave me only 22 fps in addition. I thought the difference is insignificant and uninstalled it. I don't know if you've seen the hammer weight. The only thing that holds it in place is a couple of tiny hex screws pressing against the body of the hammer. I've read opinions saying that it simply falls off after 30-40 shots. It was my first thought as well. I agree with you that turning up the reg output pressure is the key - because almost certainly the scale does not indicate pressure accurately.

 

[zx10wall]

I’ve installed this kit in (2) R3s. Without the hammer weight I couldn’t achieve the 890+ fps I wanted. If you install the hammer weight with some locktite it stays on. My Standard R3M needed an indicated 143 bar to get the 34s to 890. My R3 Long needed 130 bar to do 905 fps. I would think the Short would need at least 145-150 bar to get close to that but have very low shot count. If it were me, I’d install the hammer weight with locktite, set huma at an indicated 140 bar, find first peek and set 15 fps slower. You should get, I’m guessing, 860-865 fps with the 34s. 

 

[sen]

It is obvious that you have a vast experience with the R3s. May I ask sth else? Have you noticed that the Exact King Heavies fit a bit too tight in the mags? You need to really push hard to make the pellet fit fully into the Matador mag. And have you tried the MKIIs? Is their skirt diameter really smaller?