Vulcan 3 – .22 – 700mm New To Me – Discovery & Learning Process

Just received my new-to-me Vulcan 3 in .22 cal. with the 700mm CZ pipe. This is a gun that was new in Dec. so about 6 months old. Arrived in mint condition.

Gun came with a Regulator Tester Gauge as well as some convenient little extras. Since I am a tinkerer & always looking to improve my weapons’ smoothness and maximize accuracy I am definitely cranked to start this “project”. In this rifle the regulator is required to come Out of the Air Plenum Pipe and be put into the tester to get an accurate value, No “reg. pressure gauge” on side of rifle like many others today. The reg itself is a pretty large aluminum machined part and nothing like the little one in my Crown II.

In Previous life it was set to drive 34 gr. slugs at over 900 fps for long range target shooting. By owners account it was about 30 rnds. until time to refill. REG. was set at 130 Bar with Loads of Hammer-Spring pre load so not the nicest for Cocking smoothness. I brought hammer cap Out by 1/4” to flush with receiver and also greased the bore that the Rear of the pellet probe rides in during cocking stroke. It is a hidden path but made a very big improvement in the smoothness of the cocking cycle.

I don’t want to be pushing that heavy so I would like to Tune for 22-26 gr. Slugs and 25.4 JSB-RD’s at best accuracy I can achieve for 100 yd. Group shooting. Want to keep shot count a lot better than 30. The bottle alone is 580cc and the plenum is quite large too.

The Vulcan has an interesting design in that you can literally “Flip” the long Plenum Tube below the Action to Place Regulator in Forward end or Rear End of this Pipe in Relation to the “Popette Valve” at hammer. In doing you create Either a Huge Power-Plenum with Tons of Power capability OR a smaller sized plenum for more efficiency and higher shot count, but less horsepower.

** So far, after full disassembly (quite a busy disassembly if going all way down) and deep cleaning of barrel I set Regulator to 110 BAR and Changed its Location to the the Rear of the Plenum as described above so Not as much Power Capability.

Results at 1st Setting:
110 BAR, Small Plenum, Hammer Spring cap FLUSH with receiver and 25.4 MRD’s. = 661 fps
same, same, Harmer Spring Turned IN 1 Full Turn……. 25.4’s. = 845 fps.
Same, same, Hammer Spring Turned In 2 Full Turns ……. 25.4’s = 895 fps
Same, Same, Hammer Spring 3 Full Turns In …….. 25.4’s. = 910 fps

So Tomorrow I’ll Swap Reg to Large Plenum config and Keep at 110 Bar to See What Happens.???

After That I’ll be looking to Configure to be able to shoot 24 gr slug @ 1,050 fps. with the Hammer Spring Turned in 2-3 full turns SO I have the “Backing-Down Room” to get the ammo into Mid 800’s to 1,050 fps range just by adjusting the Hammer Spring tension easily in back of receiver.

Probably will need to Go Up a little on Reg Pressure but Don’t Know What the actual Velocity Effect will be when Kept at 110 Bar and just Swap Ends of Plenum. (good experiment)

Once things start to shake out in the Garage Tuning I will mount a new 8×34-56 Athelon on top and go Punch Paper. Can’t wait…

Airgun Technology

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QUESTION: Does someone here know How Many TURNS IN or How DEEP Into Back of Receiver is considered the Sensible Hammer Spring Compression Tuning RANGE for this rig??

Unfortunately there is Zero guidance on this from AGT papers or Instructions. Their Website is also a little “thin”.


Vulcan 3 Update: (What a Machine…)

So I did bump regulator back up to 130 Bar but Kept it in same “SMALL Plenum” location to see what I would get.

The Numbers: Small Plenum – 130 BAR – 4 Turns In on Hammer Spring
– 25.4 g. MRD’s were at 940 fps
– 20 g. ZAN’s were making 1,000 fps.
So this Regulator Bump Up 20 PSI + 1 More Hammer Spring Turn from 1st post Added about 45 fps in SMALL Plenum from before.

Flipped Regulator to LARGE Plenum Position – 130 BAR (no change) – 4 Turns In on Hammer (no change):
– 25.4 g. MRD’s were at fps 995 fps.
– 20 g. ZAN’s were making 1,053 fps.

Wow, the gun is working NO Harder than before at a very modest 130 BAR but the increase in the Volume of that “Regulated Pressure Chamber” Plenum has pushed Velocities 55 FPS Higher all else the same. (this much of change surprised me)

I have to believe that the ZAN’s can be made to fly accurately Somewhere between 950 & 1,050..(??) so I’m close I think.

Also the 25.4 MRD’s should be easy to tune down to about 970 fps with about 1 turn of Hammer Spring. I say 970 on the MRD’s because the previous owner mention that this speed showed excellent Accuracy with those pellets in this Barrel from His previous use.

No Surprise to anyone here, there ARE several inconveniences with this rifle platformIF You are a “Self-Tuner / settings-fiddler type” (Like Me) that are plain to see.

1.) The requirement to Disassemble & completely Remove the lower Air Cylinder with the bottle attached from the receiver and then Remove the End-Cap nearest the Regulator for any REG. Adjustments. (Reg. is then pushed towards that end with a dowel or grabbed with a threaded bolt to get at it.)

2.) You DO need to have a Regulator Tester (short hi-pressure cylinder with a Gauge on top and Screw-On Bottom that youput the Reg. Into and Pressurize to see changes on Gauge after adjustment). Aft adjustments and testing to set pressure you Push the Regulator Back into the Plenum and re-asseble all.

3.) Maybe the biggest bummer is the need to De-Gas the entire gun to Zero, obviously, before you can access the Regulator inside the Plenum Tube. The Ends(s) screw off quite easily / no special tools, BUT the Waste of AIR (if you only have 1 SCBA tank at home) is unfortunate.

The actions described above only takes about 15-20 minutes after all the air is out (10-15 min), but is a little tedious.

However, AFTER you get things set to where you’re Within Your Desired Velocity Ranges by just adjusting the Hammer Spring Cap at the end of the receiver, you have an awesome, hi-quality, hi-powered PCP with a 700mm CZ hammer-forged barrel and extremely rugged / rigid construction.

This Vulcan 3 does Not have an elegant “Traditional Rifle” profile that I am usually drawn to. My Crown II is the “traditional & pretty” and crazy-accurate out to 50 yds. rig, but I don’t want to Crank It Up so much to be a 100 Yd. Gun with heavy pellets & slugs. Furthermore, It can Never Even Be “Turned Into” the Power-House the Vulcan can be tuned to.

What the Vulcan 3 Does have, however, is a Great reputation for Long Range accuracy and Power Expandability with it’s Huge Regulator & Plenum into the area of an absolute Beast of a rifle. IF You Want, (and go to very hi Reg. settings, etc.), you Can push this Machine up to probably shoot 40 Gr. Plus Slugs in .22 cal at over 1,000 fps. That’s Not what I’m after right now, but it’s nice to know the Capabilty is there. Next year maybe I get a “Wild Urge”…who knows

Next Stop needs to be the Dive Shop for AIR and the Range for some shooting. Unfortunately, now getting in to the Nasty Florida Summer of heat and humidity, so it dent’s my enthusiasm a bit to go out and “soak & roast.”

We’ll see, I’ll report back afterwards.

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