GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: CraigH on October 12, 2017, 12:54:01 PM
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Another PP700 journey - My third PCP, but first experience with a regulator.
The good:
The trigger began its life with a bit of creep, but after about 150 shots smooth out to a perfect creep-free break. With just a little lightening of the pull it will be superb ;D
Fit ans finish of the exterior is excellent - very sound design. ;D
The bad:
Regulation is poor, if such even exists. I am advised the regulator takes some break in and also lightening the hammer strike will help improve curves of the shot strings. I am not ready to tear into the workings as yet since it would then not be returnable.
Pressurizing to a full fill and without any adjustments delivers shot strings as in the chart below which has a full hammer strike. Lowering the hammer force lowers the fps throughout and extends the shot count but the curve is similar, and the pressure points are also similar. The valve itself seems to like being at about 95 Bar in charts.
Reading posts and applying the information to this situation seems to indicate lack of regulator function. I will be trying regulator adjustment after I get a good metric hex set (only metrics I have are T-handle). Which directions of the adjustment determine up and down pressure? I am assuming clockwise would increase pressure.
BTW, I am looking for a pin spanner wrench. All 2mm pin spanners I have seen online are currently out of stock.
TIA
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The sear engagement and take up are adjustable, you'll have to install a screw for over travel if you want it though. The regulators on these guns are mediocre, that's why the FT guys are putting Huma regs in. Mine has been awesome for hunting and plinking. I shoot it more than anything, especially now that it's extremely quiet. It may take some more shooting for yours to settle down, I probably have 800 pellets through mine. Yes, clockwise increases the set point.
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The sear engagement and take up are adjustable, you'll have to install a screw for over travel if you want it though. The regulators on these guns are mediocre, that's why the FT guys are putting Huma regs in. Mine has been awesome for hunting and plinking. I shoot it more than anything, especially now that it's extremely quiet. It may take some more shooting for yours to settle down, I probably have 800 pellets through mine. Yes, clockwise increases the set point.
This!
I've had my MKII for a year and have in the neighborhood of 7000 pellets give or take down the bore. I shoot it daily rain or shine, and yes the reg is mediocre. I will be investing in a Huma next year. But the factory one does settle in and seems to like being near the upper range on mine. It also prefers heavier pellets as most SPA airguns do. I still am not totally happy with my trigger, but I like a long and light first stage with a medium and crisp second, but until I do a teardown, it still works excellent- perfect for hunting.
Other than the regulator possibly causing some headaches, my main issue is the breech seal. I've had a little blow-by for a couple thousand shots and some day may address it. As Matt said, clockwise increases, anti-clockwise counter-clockwise decreases. You'll get the most mileage in tuning out of your hammer spring tension, but you really need a chrono to figure out a happy point.
You can use two drifts (or perhaps 2 centerpunches) and a screwdriver to loosen the cap. You can probably make a decent pin spanner, too. I have a golf-spike tool I reworked using an angle grinder and it also works, though it ain't pretty.
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Thanks, Matt and Peter!
I'm back with standard metric hex keys for adjusting the regulator.
What I'm really not liking is the ES. Not what my understanding of regulation is - a long way to go for 4%, let alone 1% or 2%! My CO2 pistols are much better. What I do not understand as yet is how much each, the valve and the regulator, are responsible for such performance. I looked at the Huma regulator and the online instructions show that the stock regulator remains and is bridged and the Huma is inserted into the pressure tube. That decreases the pressure tube volume - I would think not ideal but workable. I'm sure Huma intended the installation to be as simple as possible without any machine work.
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Progress - In two steps. I have to take away a few points from the "Good" of "sound design" - difficult to get and keep the hex key on the regulator adjuster.
First I reduced the regulator pressure some amount, perhaps a full turn, difficult to be sure. With a 200 Bar fill the first two shots were, as seen in the graph below, quite slow, then the pistol would not fire in three attempts. Apparently no pressure coming through the regulator. I have noticed that after a fill there has been a first shot of very high velocity - in the first chrony run at over 700 fps. Maximum fill pressure seems to bypass the regulator for that shot. And in this fourth chrony run these two slow shots pass for high initial velocity before the regulator shut down the pressure. So I turned up the regulator and the hammer spring and resumed the shot string. Through what ever luck, the chrony run (excepting the first two shots which are included for completeness) looks reasonably good for an out of the box pistol. Twenty-five shots from 200 Bar to 150 Bar.
Graph is attached.
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That's looking decent. I think the fast first shot is pretty common for these. Was the gun filled when you adjusted the reg? I always empty the cylinder before I adjust it, I think I read decreasing with pressure was ok, but not increasing it. I could just be making that up though, so do your own research.
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The real misrepresentation on these pp700 pistols is the regulator. It isn't actually a true regulator, but more of a compensation valve. It basically slows the air down going into the plenum of the pistol to give the semblance of regulation. They are awesome little pistols, but they only sort of regulate. You'll notice that they will behave differently if you vary the time between shots. Essentially, the plenum will eventually reach the same pressure of the cylinder if left to sit long enough. You can get them to shoot decent strings with enough adjusting of the "regulator"/hammer spring/transfer.
Now, with all that being said, the Huma changes everything :D
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That's looking decent. I think the fast first shot is pretty common for these. Was the gun filled when you adjusted the reg? I always empty the cylinder before I adjust it, I think I read decreasing with pressure was ok, but not increasing it. I could just be making that up though, so do your own research.
There is a post suggesting adjustment at low pressure and I had the pressure down to 50 bar for the adjustment down. But when the pistol would not fire I adjusted up under full pressure. Just the opposite but it worked. Maybe the washer stack began functioning better by coincidence or happenstance.
Donny,
Thanks for you observation! The high velocity first shot and air leaking to the plenum when sitting probably have some relationship. Depending on how the pistol operates going forward and my wants/needs, a real regulator may be in the future.