Last week I returned a Gen 3 0.22 cal DAR that I bought last September because it suddenly lost 250 fps in velocity. That gun had less than 100 pellets through it. Yesterday, I got out my Gen 3 0.25 cal DAR that I also bought last September. The first 15 or so shots were fine. I then topped it off to 3000 psi and shot it and immediately noticed a drop in velocity. After about 8 or 10 shots it seemed to be back up to shooting normally. I decided to air it back up and shoot a string over the chrony. I found that the first 6 shots gradually increased from 530 fps to 725 fps which was at a gauge reading of 2900 psi. The next 30 shots were 725 fps or more with a maximum of 780 fps with pressure of 2900 down to 1600 psi. Shots 36 to 50 dropped from 725 down to 510 fps. So, I thought maybe 3000 psi is too much pressure for some reason so I filled it up to only 2600 psi thinking that would be in the sweet range but wouldn't you know, it did the same thing with the first several shots being low on velocity. To top all this off, during doing this , the gun decided to randomly dump ALL the air and now it has a slow leak which it didn't have before. This is supposedly a regulated gun, I didn't think regulated guns had this bell shaped velocity curve?? Could this be a bad regulator? bad o-rings?
DAR More DAR frustration
- Thread starter BassMan
- Start date
Its not hard to install at all. They made one for me before they started regular production on them. I had to give them the dimensions of my old one. They only charged me 34 bucks shipped to my door. I don't know what they cost but probably around $90.00
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UPDATE The new replacement 0.22 Gen3 DAR which I received in June has now also crapped the bed! Same thing, suddenly lost 255 fps in velocity. That's 3 Gen 3 DARs that have all done the same thing. At this point I don't know if I want to just toss it or invest in a new regulator. Any suggestions?
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The gradual climbing velocity is a symptom of pressure creep. It can be caused by a worn/damaged seal at the end of the regulator piston, or a failing O-ring on the brass adjuster. If you’re interested in repairing it, let me know and I’ll draft up some guidance.
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Sounds like bad O-rings, the Manufacturer probably got a batch of bad O-rings, probably an easy fix.
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Owned a DAR 1 for a brief moment. Biggest POS I’ve ever owned. Do yourself a favor and cut ties now and run.
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The velocity didn't climb it decreased. However, if it is a simple fix I'm definitely interested. Thanks!
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If your reg takes a poop and the gun suddenly becomes an unregulated gun, that would explain the -250fps. The easiest way to test that is to keep shooting. If your gun is now getting a ton of shots as you try to shoot down to 130b, probably a blown reg. If your gun starts getting faster as the pressure in the tank decreases, probably a blown reg. My buddy has a DAR whatever gen and it’s a great gun. If his reg ever poops, I’ll put a Huma in it if they make one.
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Huma makes one for the Dar but its not listed.When you click on the Airacuda Max reg is where it says also for Dar Gen 3.
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Do you have the dimensions of the Gen 3 reg Huma makes? Wondering if they are the same as the Gen 2.
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Oh, by increasing I mean your original post describing a first shot slow, then increasing:
This behavior indicates the pressure in the plenum is climbing above the intended setpoint. The elevated pressure makes it harder for the hammer to knock the valve open, resulting in slower shots. After a few shots, the pressure falls and the hammer is better able to knock the valve open and the velocity climbs.
It is a symptom I have seen many times over the years, and each time it was either a damaged valve seal in the regulator or a failing O-ring on the adjuster.
The construction of the DAR regulator is very similar to a Huma so we can refer to the following picture for guidance:
The seal - The seal I'm referring to is the little plastic disc in the middle of the photo. It is responsible for halting the transfer of air by pressing against a tiny orifice at the end of the brass adjuster (bottom right). Over time, it will become worn and the regulator will begin exhibiting a growing degree of pressure creep. You will see an indentation in the middle of the disc. Simply flip it over to expose a fresh surface.
Or if down the road both surfaces are worn, wet sand it against a granite countertop or piece of glass to level the surface, starting somewhere around 600 grit and carry it out to 2000 or so. Holding it with a piece of masking tape makes the process go quickly and easily.
The adjuster - The brass adjuster is another potential source of pressure creep. The O-ring will harden over time due to thermal stress and begin slowly leaking. You can use a common Buna-N O-ring to replace it but if you can source a Viton, it will last longer.
Important note...before removing the brass adjuster from the regulator body, make a Sharpie or nail polish mark across them, and measure the overall length of the regulator with calipers. That way you can return the adjuster to the same position as before, and preserve something pretty close to the original setpoint. Otherwise you may find yourself in a frustrating cycle of disassembly/reassembly to get it back to the right pressure.
Miscellaneous - It may go without saying but it's a good idea to go ahead and replace all the regulator O-rings while you have it apart. At the very least, replace the one on the small end of the spool because it is subject to heat stress like the one on the adjuster.
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Here's a DAR Gen 2 regulator taken apart.
The black section is only the carrier for the regulator in the air tube. I've beveled that as you can see to make it easier to press the Regulator back into it and not sheer the o-rings.
One thing I don't like. The Delrin seal (white disk) is 1 mm thick. The point on the Brass part is .5 mm and has nearly cut through that. Flipping it over I'd suspect a short life fix. The dimensions of the delrin is 1 mm thick by 6.95 mm diameter. I'm thinking of making a new one and taking a bit off the brass part.
Near the belleville washer stack you can see an o-ring. That is actually just a part that has sheered off. I don't think it has any air pressure and just holds the stack in place when assembling stuff.
The black section is only the carrier for the regulator in the air tube. I've beveled that as you can see to make it easier to press the Regulator back into it and not sheer the o-rings.
One thing I don't like. The Delrin seal (white disk) is 1 mm thick. The point on the Brass part is .5 mm and has nearly cut through that. Flipping it over I'd suspect a short life fix. The dimensions of the delrin is 1 mm thick by 6.95 mm diameter. I'm thinking of making a new one and taking a bit off the brass part.
Near the belleville washer stack you can see an o-ring. That is actually just a part that has sheered off. I don't think it has any air pressure and just holds the stack in place when assembling stuff.
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FWIW, I blunted the “volcano” orifice a little when I rebuilt mine. Wet sanded and polished.
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Man after my own thoughts!
Looking real close at the design and that failed o-ring near the belleville washers? I'm thinking that was my 1 PSI per minute leak.
I'm going to see if I can cut a slight bevel inside the Regulator body in that area. What I see is no bevel or a rough bevel?
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A very slight radius or bevel is reasonable if the O-ring is getting shaved when reinstalling the piston. The engagement depth of this O-ring (narrow end of piston) is usually not very generous on most regulators, and appears to hold true in this instance based on the Belleville stack shown in your photograph. Just saying anything more than a slight bevel could produce a leak.
Mine also had no lead-in but a little silicone grease on the metal and the O-ring allowed it to go together successfully.
The original size of this O-ring is a M1.5 x 3. I wanted to use Viton but I didn't have this particular size on hand so I took the nearest dash size, a -005, and abraded its ID using a conical diamond burr until the thickness was reduced from 0.070" to 0.060".
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