Wolverine MTW fps increase with increased applied hop

[zulu058]

I just wanted to get a little bit of input on this. I've seen similar results in BASRs, which do tend to be overvolumed compared to other platforms. In fact, I have a recent post about a similar phenomenon with my L96. However, these are two different types of systems and I'm much less familiar with what behavior I can expect from an HPA system.

With hop up turned all the way off, regardless of bucking/nub setup, I see a decrease in fps and sometimes (depending on setup) also a slight increase in fps variation. With hop up increased, the fps increases and stabilizes. I'm assuming this is due to an increased pressure spike building up behind the bb on higher hop up settings. However, I'd be curious to hear others' input on this.

This has happened (it may have happened with more setups, but this is what I can recall/have recently tested) with R hop + modify black bucking + M-nub, R hop + modify black bucking + modify flat nub, Maple leaf macaron + omega nub, begadi bucking + omega nub (I have tried both a glued nub and one that is not in many of these scenarios). The gun shoots consistently. It could be slightly better, but we're talking soda can accuracy at 80', which I'm happy with. I have field tested many of these setups but have a difficult time getting measurable and quantifiable results in the middle of a game day, due to my field's range also being short and long distance testing only really being possible on the field. My best results, grouping wise, were with R hop -- with the maple leaf macaron only slightly worse.

I have an EMG atlas on the way as a test of another flat hopped bucking to make an airseal comparison, as well as an airtech flat nub + R hop nub package. I have already flat hopped a G&G green for comparison and didn't see any major changes.

I'm seeing consistent results across different hop up setups. However, as an example, with my current setup (r-hop) the rifle shoots ~255 fps with 0.4's on minimum hop up, and 295 fps with 0.4's on appropriate hop up to lift .4s on a flat trajectory. With 0.3g bbs, I'm at 305 fps with an even trajectory and 330 fps with overhop. The fps variation is less, and the joule variation is even less than that, which would make sense if the heavier bb is lending itself to a greater pressure spike. This is at roughly 85 psi to hit field limits. I'm testing with 1.5J as my goal baseline. I can shoot without holdover to 225' consistently with the R hop setup. I have made shots on a stationary target in the open to 300' with man-sized holdover and multiple bbs fired.

The only concern is that I have a narrower possible adjustment range for a range of BB weights. I.e. when hopping 0.3's, I would see an overall power decrease unless I adjusted my reg. Adjusting the reg does alter the FPS results but general behavior between hopup settings remains the same.

Occasionally, I will see 1-2 inconsistent shots before the system warms up. These are almost always low fps readings. Trajectory change is noticeable. Then it gets much more consistent with anywhere between +/- 1-4 fps depending on bucking + nub set up. Maple leaf is most consistent with appropriate hop at +/- 0.5fps. R hop is least consistent in fps/joules at +/-3-4 fps depending on series of 10 shots I'm taking (but most consistent in groupings). This would make sense if the pressure spike is improving consistency of bb contact with patch (patch protrudes further/creates more resistance with the maple leaf than the R hop). It would also make sense if the maple leaf just seals better in general.

The nozzle:bucking seal should be good but is the only place I could possibly be getting an air leak (tested water seal of the whole engine) which is the only other thing that may be associated with this problem. The question is whether this sounds like an air leak to everyone (if so, there's jack all I can do to fix it, it happens with both stock and SI nozzle with many different buckings), or if it's an expected behavior of the system. Dwell is set appropriately for 0.4's. Nozzle has a very small amount of play but it is there.

Anyone who runs with and is familiar with an HPA system in general is welcome to chime in. Also curious to see if this occurs to people running closed bolt systems, too.

Sorry for the essay, all. Thank you in advance!