Power Plenum ~ Taipan Veteran

@mtnGhost

Put me down for one in .22!

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Well I did it. Seeing tremendous results with these new components in my Vet. Finally got out today to test out this new valve body design and the newer barrel adapter that I prototyped. I think the seating depth is a lot better than the other design, which seems to show much better with accuracy and consistency. Efficiency-wise, The head of my valve body is longer than the factory body, so it puts heavier compression on the valve spring. The valve pin itself is using a softer, but high quality acetyl polymer on a titanium pin (and it weighs almost nothing lol). Just using the factory spring with a harder POM-H spacer, which I spent a fair bit if time determining the minimal length for best power range through HST adjustment.

Using the 600mm slug liner from a Crown (one that I took off the rifle I bought from @bob_o), I'm seeing hole in hole accuracy at 102 meters (~114y?) with 24.8gr NSAs. This thing is quiet too with the Taipan LDC screwed on the end of the FX barrel kit. The problem with using the LDC was solving for a gap in the inside diameter of the breech-side, since the Taipan barrels are larger diameter than FX sleeves. Simple solution - I "borrowed" the shaft collar from the Crown barrel kit's shroud to use as a compression point for an o-ring that gets sandwiched between the collar and LDC .. it might not be elegant and seem low tech, but it does the job:




Overall, this thing is still pretty short, and I can lose ~4" by removing the moderator if need be. I'm still tempted to test the 700mm kit, but at 147bar and sightly dialed back on the HST, I'm sending the 24.8's at 915FPS with p r e c i s i o n accuracy

Quick question. Since the FX Sleeve has a smaller diameter than the Taipan barrel, how did you snug up the barrel inside the brackets that connect the barrel to the rail and air cylinder?

Yeah similar setup as Derrick. As ghetto as it may sound, thin Delrin split sleeves and Gorilla tape . The barrel was secure on its own with just tape, but I just wanted extra insurance until I decided what I want permanently.

For those interested, you can buy the power plenum from Ernest here:

https://www.ebay.com/itm/Taipan-Vetern-Reg-Tube-Exterson/23341931000

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Are these still available..looks like the listing has expired? 

Looked on Ernest's website but didn't see them either...

Sold out. I messaged Ernest Rowe on Instagram to see if he was printing more, but never got a reply. I might need to get some made in a couple of different lengths anyway

This has been a really interesting thread!

I've been trying to get my .22 Taipan Veteran Long to shoot the RD monsters, currently I can only shoot them at ~860 fps and they become unstabilized somewhere between 10m and 120 yards.

I bought a power spring from Talon Tunes, but now I'm wondering if I should compliment that with a power plenum (and perhaps other mods)...

Really cool read to see what you guys have done with your Veterans!

Looks like Ernest no longer is selling these?

Looks like Ernest no longer is selling these?

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I would have had a dozen extra 40cc plenums tapped for reg manometers if this damned pandemic hadn't happened!!! 

This has been a really interesting thread!

I've been trying to get my .22 Taipan Veteran Long to shoot the RD monsters, currently I can only shoot them at ~860 fps and they become unstabilized somewhere between 10m and 120 yards.

I bought a power spring from Talon Tunes, but now I'm wondering if I should compliment that with a power plenum (and perhaps other mods)...

Really cool read to see what you guys have done with your Veterans!

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You could probably post a WTB add. I’d bet someone purchased a Vet Power Plenum that never installed it or decided they didn’t need it. 

I’ve tuned a .22 Vet Long. I didn’t add a Power Plenum as they were not available at the time. I was able to get the 25.39 gr RD Monsters well over 900 fps but best I can recall, I dialed it for 905 fps or so. I believe it got around 35-40 shots on a fill. This was accomplished with porting and polishing the valve and adding a slightly stronger hammer spring. @Deepbass9 has it now. David would probably share specifics on its performance.

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Awesome, thanks for the info!

Don't expect massive velocity gains with plenums extensions. They're only providing 15FPS each with the factory valves on their own. Heavier springs and higher pressure is the next real leap in velocity (hammer weights are also desirable for longer barrels). Beyond that involves upgrading to a higher performance valve system.

I’ve tuned a .22 Vet Long. I didn’t add a Power Plenum as they were not available at the time. I was able to get the 25.39 gr RD Monsters well over 900 fps but best I can recall, I dialed it for 905 fps or so. I believe it got around 35-40 shots on a fill. This was accomplished with porting and polishing the valve and adding a slightly stronger hammer spring. @Deepbass9 has it now. David would probably share specifics on its performance.

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This gun is a lazer and without a doubt my best and favorite shooter. It was tuned at 895 fps for 45 fpe with the RD's for 40 shots. I bagged a couple of the Bushnell Forge scopes on the rebate deals they were running, so it's got a 5-20x44 FFP on it now. Yea, I know it was only 25 yrds, but I dialed in on a nutter 2 days ago and the smack down was on point and authoritative. Nothing like putting the lead on the dot, and the dot on the noggin. It was DRT with no fancy dance.

I actually haven't chrono'ed it with the RD's since I've gotten it from you, Derek. It's never missed the mark, dropped the POI, or given me cause to wonder if anything has changed. I tried some slugs at 100 through it, but it didn't like them, and those I did chrono. But 40 shots at least and a sweet, sweet .22 long that will never leave my "herd". The one and only trade I ever made and I am certainly glad Derek talked me into it. Especially since I was all bone-headed about it

Range of accuracy for me is up to 80 yards. I can nail 1.5" spinners off-hand, crouched and knee down. Easily. I didn't bother at 100 as I was really just trying out the slugs and don't plan on hunting anything at that range with that caliber.

Well, as much as I admire, like, and respect you...and I can say you would certainly be 1st in line...I don't think this one is going. Doesn't look like the Cricket is either. Which is fine by me, though I can't hunt with it. Maybe not so fine with the wife, though. I was trying to swap it for a Rowe tune Cricket .22, but I got screwed. I'm still working on the guy, but I think he got locked up...whatever. Not a scam, just a confluence of circumstances and bad luck for me.

As for the slugs, I have 2 of the .22 sample packs and just looked and didn't seem to have any 20.2's. Then I checked another storage box and they were in there. I had them slated to try in lighter powered guns and I have 39 and 40 of each, so it looks like I never tried them in the Vet. I guess I should really have said, I tried some slugs in it, but the ones I tried it didn't like as I still have most of them.

Anyway, which diameter did you find they like, the .217 or .218's? Might as well glean all I can from ya

The CZ barrels are pretty tightly choked. They don't like the .218. Mine likes even smaller than .217. Best results so far have been with .2155 diameter slugs.

I would give the H&N's a shot too. The 25gr seems to work very well with "medium" length airgun barrels with similar twist rates.

Those CZ barrels are something else. I had a 452 long ago that was super easy to clean and laser accurate with literally anything in 22lr that I fed it. The CZ in my Mutant shorty is literally perfect. The bore is pristine, and they did an excellent job smithing the chamber / throat, crown and LDC threading. I can shoot 1,000 pellets and only need one wet and one dry patch to clean it. Unfortunately the new barrels are the polar opposite. The original barrel in my standard Vet is the worst that I have ever seen.

Don't expect massive velocity gains with plenums extensions. They're only providing 15FPS each with the factory valves on their own. Heavier springs and higher pressure is the next real leap in velocity (hammer weights are also desirable for longer barrels). Beyond that involves upgrading to a higher performance valve system.

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I'd say, borrowing your hammer strike is producing sufficient dwell, the addition of the first plenum adds 25-30 fps. Each there after is a diminishing return.

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700mm .25?

Nice. I picked up a Leshiy "classic" w/250 .22 and a .30. I'll try the .217's in the Vet and the Leshiy.

I tried to get Dillon's Ed .30 Long...he told me it was mine, but then missed my PM back. I was bummed but I really couldn't have gotten that one it without moving something. I can't believe no bites on the Cricket. It is without a doubt on par with the Vet long. 

I should try to move my Flex .30 and have the cash ready for a Ed .30 as they've been up a few times this past year, but now does not seem to be the time for WAR's to move. Think I'll just try putting a Tatsu on it to shorten it up, as now that I've worked the niggles out of it, it is one hell of a tack driver. I haven't touched it since you set the reg for me, Derek, but I worked out a couple of small issues, put a Magpul PRS on it and power and accuracy to spare. But 47" now..drop to 43" with a Tatsu...vs, what? 38" for an Ed .30? And probably 2# lighter than my current config...

But it does kill..