Tuning Diagnostic Help with Taipan Veteran Long .25

[WorriedMan]

Background: Purchased Taipan Veteran .22 Standard from Utah Airguns on 12/19/21. Mounted scope, sighted in, shooting 18.1 grain JSBs, like a laser beam, ever since, crazy accurate. So impressed, on 2/22/22, purchased another from Utah in .25 Long. Shooting both JSB 33.95 grain and 25.39 grain, accuracy is inconsistant, at times, accuracy to rival the .22, at other times, 2-3 inch groups at 50 yards. Accuracy with JSB 33.95 King Heavies, seems best, gun has not been modded or adjusted, in any way.

Today: Shot three sets with chronograph, using JSB 33.95 grains. Results; (8-shot group) Median 795.7 ES 12.3 SD 3.648

(9-shot group) Median 749.6 ES 45.3 SD 15.14

(10-shot group) Median 795.4 ES 12.2 SD 4.317

After collecting chrono data, I shot another 10-shot group, without chrono, first four shots to dial in scope, switched to another target for last 6 shots. Inner circle is dime size, @ 50 yards. 

Can anyone offer a suggestion as to what caused the 9-shot group to be so different? Thanks, WM

 

[Franklink]

If I'm reading it right, that 9 shot group was about 50fps slower, and had a much larger ES.

Were you above regulator pressure (factory reg is probably around 125 if anything like the ones I own in .22) for all three groups? 

All the same tin of pellets?

Any chance that you've got one bad magazine? It'd have to be really out of alignment to have that much influence on the chrono, but is one mag rough or difficult to close the bolt on? Just thinking maybe one mag is out of alignment enough to be taking big bites out of the skirts or something. 

 

[WorriedMan]

Franklink,

First group, gun was at 250 bar, now showing 165 bar. Same mag, same tin. Yeah, and you're reading it right, pellets were all over before settling down at 10-shot chrono group. You can see the accuracy of the last 10-shot, non-chrono group. WM

 

[elh0102]

If it was just the accuracy, I would suggest it might be a fouled bore. But, that wouldn't explain the ES in velocity. If you're getting inconsistent accuracy with good chrono numbers, I'd clean the barrel. If the velocity consistency continues as a problem, I might be suspicious of the regulator.

 

[MikeBell]

You are shooting too slow. Not enough hammer spring tension for the regulator setting.

 

[WorriedMan]

elh0102

Cleaned barrel, just like I do with all new guns, Ballistol and Patch Worm, gave this gun a second barrel cleaning just to rule that out. As you can see, problem still persists. Leaning towards regulator myself but want to hear from those more experienced, before calling Utah Airguns. WM

 

[Cannonball]

You are shooting too slow. Not enough hammer spring tension for the regulator setting.

This right here. Crank up the HST till you can’t cock the gun, then back it off about 1/4 turn. You should be hitting 910-920 range with the 33.95’s. Once you are there, refill it and shoot a complete string and report back. I bet that fixes your issue. If you want to shoot the 25 grain, you will need to lower the regulator pressure unless you want to send them out pushing supersonic speeds.

 

[Franklink]

You are shooting too slow. Not enough hammer spring tension for the regulator setting.

I had that thought but then realized he's just shy of 50fpe. I don't have any experience with the .25 Vets but that's just about all my .22s will do, even with plenum additions, slightly longer barrel, reg increases, and oem hammer spring nearly maxed out. 

Is 48 fpe on the low end of what the .25 Vets can do? 

I'm thinkin elh0102's suggestion to check out the regulator might be worth looking into. I just bought a used Vet that was having much wider spreads than I'm used to seeing. I replaced the orings in the regulator and now its just as consistent as I'm used to. 

So, maybe increase the hammer tension a bit first to see if it'll shoot more consistently? If that doesn't resolve it......I'd personally be leaning towards new orings in regulator. 

 

[Cannonball]

If I'm reading it right, that 9 shot group was about 50fps slower, and had a much larger ES.

Were you above regulator pressure (factory reg is probably around 125 if anything like the ones I own in .22) for all three groups? 

All the same tin of pellets?

Any chance that you've got one bad magazine? It'd have to be really out of alignment to have that much influence on the chrono, but is one mag rough or difficult to close the bolt on? Just thinking maybe one mag is out of alignment enough to be taking big bites out of the skirts or something.

My 22 long is factory set to right around 125 bar, but my 25 compact is almost 150 bar from the factory. 

 

[Cannonball]

You are shooting too slow. Not enough hammer spring tension for the regulator setting.

I had that thought but then realized he's just shy of 50fpe. I don't have any experience with the .25 Vets but that's just about all my .22s will do, even with plenum additions, slightly longer barrel, reg increases, and oem hammer spring nearly maxed out. 

Is 48 fpe on the low end of what the .25 Vets can do? 

I'm thinkin elh0102's suggestion to check out the regulator might be worth looking into. I just bought a used Vet that was having much wider spreads than I'm used to seeing. I replaced the orings in the regulator and now its just as consistent as I'm used to. 

So, maybe increase the hammer tension a bit first to see if it'll shoot more consistently? If that doesn't resolve it......I'd personally be leaning towards new orings in regulator.

A .25 Vet long will shoot 65 FPE, my shorty .25 will hit 50 FPE.

 

[Franklink]

If I'm reading it right, that 9 shot group was about 50fps slower, and had a much larger ES.

Were you above regulator pressure (factory reg is probably around 125 if anything like the ones I own in .22) for all three groups? 

All the same tin of pellets?

Any chance that you've got one bad magazine? It'd have to be really out of alignment to have that much influence on the chrono, but is one mag rough or difficult to close the bolt on? Just thinking maybe one mag is out of alignment enough to be taking big bites out of the skirts or something.

My 22 long is factory set to right around 125 bar, but my 25 compact is almost 150 bar from the factory.

Ahh, okay. Yeah, my .22 Long had 125 written in red marker on the reg. Didn't know the .25s come set that high. 

I bumped the reg in mine to 155ish and it would push the 25.4gr (again, in .22) up to 960, but that is all the gun has, at least without further mods like heavier hammer springs, or hammer weights or fiddling with valve spring, porting, etc. 

 

[Franklink]

You are shooting too slow. Not enough hammer spring tension for the regulator setting.

I had that thought but then realized he's just shy of 50fpe. I don't have any experience with the .25 Vets but that's just about all my .22s will do, even with plenum additions, slightly longer barrel, reg increases, and oem hammer spring nearly maxed out. 

Is 48 fpe on the low end of what the .25 Vets can do? 

I'm thinkin elh0102's suggestion to check out the regulator might be worth looking into. I just bought a used Vet that was having much wider spreads than I'm used to seeing. I replaced the orings in the regulator and now its just as consistent as I'm used to. 

So, maybe increase the hammer tension a bit first to see if it'll shoot more consistently? If that doesn't resolve it......I'd personally be leaning towards new orings in regulator.

A .25 Vet long will shoot 65 FPE, my shorty .25 will hit 50 FPE.

Cool that the Shorty .25 will go that high. A .22 Shorty maxes out around 33-34fpe. I'd bet a .25 Shorty is loud at 50 fpe though. short little barrel. 

 

[Cannonball]

You are shooting too slow. Not enough hammer spring tension for the regulator setting.

I had that thought but then realized he's just shy of 50fpe. I don't have any experience with the .25 Vets but that's just about all my .22s will do, even with plenum additions, slightly longer barrel, reg increases, and oem hammer spring nearly maxed out. 

Is 48 fpe on the low end of what the .25 Vets can do? 

I'm thinkin elh0102's suggestion to check out the regulator might be worth looking into. I just bought a used Vet that was having much wider spreads than I'm used to seeing. I replaced the orings in the regulator and now its just as consistent as I'm used to. 

So, maybe increase the hammer tension a bit first to see if it'll shoot more consistently? If that doesn't resolve it......I'd personally be leaning towards new orings in regulator.

A .25 Vet long will shoot 65 FPE, my shorty .25 will hit 50 FPE.

Cool that the Shorty .25 will go that high. A .22 Shorty maxes out around 33-34fpe. I'd bet a .25 Shorty is loud at 50 fpe though. short little barrel.

Seems quite to me..

 

[Franklink]

lol, yeah, BIG honking moderator on there. 

The short OAL is one of the reasons I like the Veteran platform. 

And that's perfectly fine. You like the hand cannon route. I like the quiet and short and sneaky and lots of shots route. Neat that the gun can do both and make us both happy. 

 

[WorriedMan]

Just sent an e-mail to Utah Airguns, sharing this information and requesting assistance. Utah set it up for, and I prefer using, the 25.39 grain JSBs but the erratic accuracy is even worse. Dime-size groups to 3+"@ 50 yds, then back again to dime-size, for no reason. I'll try some chrono work with the 25.39s, then wait to hear from Utah. Thanks for all the help and suggestions, Cannonball, I'll try the HST adjust, if all else fails and report back. WM

 

[Franklink]

Just sent an e-mail to Utah Airguns, sharing this information and requesting assistance. Utah set it up for, and I prefer using, the 25.39 grain JSBs but the erratic accuracy is even worse. Dime-size groups to 3+"@ 50 yds, then back again to dime-size, for no reason. I'll try some chrono work with the 25.39s, then wait to hear from Utah. Thanks for all the help and suggestions, Cannonball, I'll try the HST adjust, if all else fails and report back. WM

Yes, please let us know about the outcome. 

 

[WorriedMan]

Will do, bought a bunch of JSB (25.39 grain) from Zans Projectiles but none of my .25s like them. I hope this Taipan Vet will, eventually. I'll report what Utah has to say, as well as chrono test of 25.39s. Franklink, may need some pointers should new O rings be needed on regulator. Thanks again, always can count on AGN when help is needed. WM 

 

[Franklink]

I found a list online somewhere and I think this is every oring in the Vet, copied and pasted from the invoice of my recent order from orings com. 

I think the last three on there are the sizes for the regulator. 

I've since learned that I maybe should have done 90D for the reg orings. 

https://www.airgunnation.com/topic/oring-duro-and-material-specifically-in-regulators-another-mostly-taipan-post/?referrer=1

 

[WorriedMan]

Thank you, sir.

 

[Cannonball]

Just sent an e-mail to Utah Airguns, sharing this information and requesting assistance. Utah set it up for, and I prefer using, the 25.39 grain JSBs but the erratic accuracy is even worse. Dime-size groups to 3+"@ 50 yds, then back again to dime-size, for no reason. I'll try some chrono work with the 25.39s, then wait to hear from Utah. Thanks for all the help and suggestions, Cannonball, I'll try the HST adjust, if all else fails and report back. WM

WM - I’m confident what I’m telling you is correct as I have 3 Vets and they will all to some extent do the same thing yours is doing when the HST is turned down a considerable amount. My .177 standard is the least affected, the .22 long a little more and my .25 compact sees the most extreme spread of all three when turned down, due to having the highest set regulator pressure. I think your Taipan is fine, it’s your tune that is messed up. If you want to shoot the 25.39’s you will need to reduce your regulator pressure to get the consistency you want. The good news is your shot count should go up as well. I would crank up the HST and shoot a string of the 33.95’s before calling Utah or burning through any more of the 25.39’s.