Help. Weird thing happened to my Taipan Vet reg.

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DanielL

DanielL

Member
Nov 15, 2019
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Michigan, United States
At least I'm guessing it's the regulator.

Was shooting 26.8 gr. NSA slugs and getting about 850 fps. Then at around 160 bar it seemed to fall off the reg but instead of losing velocity it gained. So I was curious and shot two and a half more magazines where it went up to 890 fps then back down to 810 fps.

I charged it back up to try the 29 gr. NSAs and it had a huge variance from shot to shot. Weirder it would go back and forth between the two velocity ranges. The string looked like this. 803, 738, 798, 777, 822, 754, 805, 756, 806, 748, 800, 751, 810, 754, 810, 758, 812, 765, 817, 768, 820, 772, 816, 774, ,820, 780, 823, 784, 819, 786... Very strange. If you looked at each other one it wouldn't have been bad. Accuracy was terrible.

I then went back to the 26.8's (pressure now at about 210 bar) and got similar but not quite as extreme behavior. 857, 831, 857, 824, 843, 815, 839, 813, 831, 813...

Any ideas what is going on?
 
I would check and make sure the breech probe o-ring is not leaking.



As to ANY regulated pcp gaining speed when coming off regulation is telling that the reg pressure it too high for the hammer strike energy in use.

Valve is operating on the down slope of efficiency peak trending towards valve lock and as pressure falls away the valve is able to open further and gun makes more power because of this.
 
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I would check and make sure the breech probe o-ring is not leaking.



As to ANY regulated pcp gaining speed when coming off regulation is telling that the reg pressure it too high for the hammer strike energy in use.

Valve is operating on the down slope of efficiency peak trending towards valve lock and as pressure falls away the valve is able to open further and gun makes more power because of this.
Click to expand...

I thought the same thing when it started rising. I followed it to see where it peaked because I figured I could lower the reg to that pressure and get equal performance with more shots per fill. Than the thing went wonky and I lost confidence in that as the reason.

I don't understand how a breech seal could have the weird oscillating velocity profile. If you break apart the two different velocities...choosing every other one...the spreads of the two groups actually don't look bad. Feels like something weird is going on. Like maybe the regulator doesn't cycle fully on the first shot...then does the next...and back and forth. It would be easier to know what was going on if the gun included a reg pressure gauge.
 
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I run my Veteran with less hammer spring than I should, for the reg pressure, like Scott described. 

First 80ish shots are within 10-12fps until I get down to the reg pressure. At that point, the fps climbs up another 20fps or so, progressively over the course of 6-8 shots, and then comes back down, again, progressively over about another 10-14shots. If fps were plotted, there would be a pretty flat line for all the shots above the reg pressure, than a bell curve, and that would eventually drop off if I kept shooting.

Mines got the OEM Taipan regulator and I've never messed with it. The only goofy thing my factory regulator does is throw a low fps shot on the first shot after the gun has sat for a few days. Nothing like the erratic fps you've described. 

Bought mine from RL Airguns in Colorado Springs a couple years ago. I was told by them that most of the Veterans have factory reg pressures set around 140bar. 

I've got no suggestions for what you're experiencing, just thought a description of how mine behaves might be helpful. 

Edit: depending on what's been done to the gun.... are you at one extreme or the other with hammer tension to where it could be binding or slipping off and on the little hammer spring alignment pin? That seems like it could give it quite varying hammer strikes, from one shot to the next. 
 
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Edit: depending on what's been done to the gun.... are you at one extreme or the other with hammer tension to where it could be binding or slipping off and on the little hammer spring alignment pin? That seems like it could give it quite varying hammer strikes, from one shot to the next.
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I don't know...unless the reg was set too high and the hammer is maxed out to get to the velocities. It didn't do this before I let the pressure fall off the regulator that is why I was thinking the problem maybe existed there.


 
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Is this only a problem with slugs or were they shooting consistently before?

One thing I would do for good measure is inspect the brass guide that the hammer rides in. My hammer was a little rough going in and out in both my Veteran and my Mutant. If the hammer sticks, the bore of the brass guide needs to be polished (the hammer may also need a light polish too).

The best way to inspect it is to degas the gun, remove the trigger plate, and remove the little sear / hammer stop part that prevents it from coming out (2nd piece from the right, I can send you a photo if you need it). When the hammer is free, you'll have much better access to test for binding / sticking, and with the valve body out you'll also be able to visually inspect the bore.

You can polish it without removing it from the block. It's a good idea in general to at least clean it. Ditto for the valve body - the bore that the pin rides in can get gritty and cause some sticking. Just be very careful not to scratch the face of the valve body, otherwise it will not seal properly thereafter. The trick for getting it out is simple:

  • Unscrew the grub screw underneath (4mm hex for the Vet, 3mm for Mutant)
  • Carefully remove the 14x2mm o-ring
  • Take a chunk of cotton off of a Q-Tip, stick it in the bore of the valve body and then pull it out (magic) 

Do not over-polish either of the brass components! When they're in need of polishing, the ES can get a little ugly.
 
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Is this only a problem with slugs or were they shooting consistently before?

One thing I would do for good measure is inspect the brass guide that the hammer rides in. My hammer was a little rough going in and out in both my Veteran and my Mutant. If the hammer sticks, the bore of the brass guide needs to be polished (the hammer may also need a light polish too).

The best way to inspect it is to degas the gun, remove the trigger plate, and remove the little sear / hammer stop part that prevents it from coming out (2nd piece from the right, I can send you a photo if you need it). When the hammer is free, you'll have much better access to test for binding / sticking, and with the valve body out you'll also be able to visually inspect the bore.

You can polish it without removing it from the block. It's a good idea in general to at least clean it. Ditto for the valve body - the bore that the pin rides in can get gritty and cause some sticking. Just be very careful not to scratch the face of the valve body, otherwise it will not seal properly thereafter. The trick for getting it out is simple:

  • Unscrew the grub screw underneath (4mm hex for the Vet, 3mm for Mutant)
  • Carefully remove the 14x2mm o-ring
  • Take a chunk of cotton off of a Q-Tip, stick it in the bore of the valve body and then pull it out (magic) 

Do not over-polish either of the brass components! When they're in need of polishing, the ES can get a little ugly.
Click to expand...

The gun is new to me. The previous owner bought it from Talontunes and barely worked it in. The first shot string was pretty consistent, though not as good as my older Taipan standard with LW barrel (this one is the long version with a CZ barrel.) I had hoped to do an A to B comparison LW vs. CZ, 580mm vs. 480mm barrel length. This went South fast. 😢

Thanks for the tips. I wonder if something found it's way into the valves. I'll check out the hammer to see if something is going on there.

The weirdest thing is how consistently it goes from one velocity to another. I've never seen anything like that. If you divide the groups into evens and odds shots the velocity consistency is pretty good. ❔ 


 
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Sounds like the regulator to me as well but I can't think why the velocities would be so erratic. My experience is that when a regulator stops working that it stops working all the time. If it were my rifle I would degas the gun, remove the regulator, adjust it down a few notches, install it again and see if the adjustment snaps it back into working correctly.
 
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Thanks for the tips. Looks like I'll need to tear it open and check the hammer and spring for any binding. Will also pull reg and clean it and turn it down slightly to see if that helps.
Click to expand...

The factory spring isn't really good enough to crack open the valve efficiently at 160bar. You'd need more energy, which could also explain the erratic behavior (I don't know I missed 160bar in your first post) .

I don't think you need to be up that high for light slugs though. 140-145bar seems about right to me.
 
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Thanks for the tips. Looks like I'll need to tear it open and check the hammer and spring for any binding. Will also pull reg and clean it and turn it down slightly to see if that helps.
Click to expand...

The factory spring isn't really good enough to crack open the valve efficiently at 160bar. You'd need more energy, which could also explain the erratic behavior (I don't know I missed 160bar in your first post) .

I don't think you need to be up that high for light slugs though. 140-145bar seems about right to me.
Click to expand...

Good point. I'm also not quite sure if it was 160 bar. The regulator sounds like top on the list. I sure don't like the trial and error required to get the pressure where you want it for an internal regulator!
 
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