Airgun Technologies Vulcan 3 / .22 - 700 pushing up Velocity for 34 gr. Slugs

[RadarMan]

Hello Gents, I’m trying for the speed that seems to be mentioned as “Best” velocity for the AVS & ZAN 33 & 34 gr. Slugs. Today I went from 140 Bar to 160 Bar on the regulator and gained 60 fps… Before was 925 and now 985. This is with the Hammer adjustment turned All the way in until Just able to engage Sear with quite a bit of finish effort on the cocking lever. (That spot seems to be about 5.75 rotation In from all way backed out to hit the stock)

I have read a few accounts of wanting to get those 33-34 slugs up to 1,010-1,020 fps to maximize their accuracy at 100 Yds.

Unfortunately, have to leave town for this week but when back next WE I’ll go the last little step to Max. Rated 170 Bar on the reg. and see what I get.

Info point, it looks like probably 2 Bar per shot at 160 reg. If 50 bar divided by 25 shots holds true. ( edited as I noticed earlier screw-up… 50 bar drop not 500!!)

ANY / ALL comments, tips, helpful input Encouraged.

Thanks and updates to follow next week.

 

[Centercut]

I think too much emphasis is placed on speed. IMHO, if the barrel is good with a proper twist rate and stability factor for a well designed slug, it should be just as accurate at 875 as at 1025 fps.

 

[ChuckHunter]

Pretty sure you will need an upgraded hammer spring to get the numbers your looking for. And Centercut is right speed isn't always the ticket! Finding the right balance for supreme accuracy is the ticket in my book. Every rifle is different and need to test and test some more to find that sweet spot for distance shooting.

 

[zx10wall]

I shoot 33gr Zans at 1010 fps from my .22 V3 - 700. I'm at 170 bar and I did upgrade the hammer spring. It's very accurate.

 

[zx10wall]

 

[Long_Shot]

You say - "ANY / ALL comments, tips, helpful input Encouraged"
Then I'd say to put a balance valve with a larger poppet and transfer port opening in it.
A much lighter HS. (easy cocking) and a reg. setting at 115 - 125 bar.
Then you could shoot 40 gr. slugs in the 900 - 950 FPS range accurately with a LOT quieter gun that's not maxed out.
I've considered getting one of these Vulcan 3 in .25 cal. for months to do this with just for another project.
But, I already have a slug gun I built this way, so I probably wouldn't shoot the Vulcan much.
It would be more work for you, but well worth it from my experience.

 

[RadarMan]

Thanks for the input Gang. "Long-Shot", that is a brilliant replacement valve (replaces plenum tube end???) if it brings that kind of performance at such low Reg. pressures. Fascinating. (You should make that think and sell examples $$)

D. Wall.. Appreciate your input in here too. In that Hammer Spring upgrade are you just ordering the example offered by TalonTunes? Also, with the heavier hammer spring, do you still find need to Screw that adjuster cap all the way in to it's Max setting (about 5.75 Turns into receiver block) or can you have it at a "Nicer" 4-4 1/2 in for much less "Stressed" sear-cocking point in the cocking-lever stroke? It is a PITA to have to pull so hard for that "click". It can't be good for the linkage.
Did you find that pushing those 33-34 gr. slugs over the 1,000 fps mark (rather than shooting them at about 950) actually made a noticeable improvement in their down-range Accuracy / Consistency?? OR what is more just to chase a Flatter Shooting gun for easier sighting and range changes?

Thanks Again Folks, Steve

 

[RadarMan]

VULCAN 33 / .22 Cal / 700mm @ 160 Bar test: See results from 160 Bar Test string with .22 Caliber 33gr ZAN / 0.218 Slugs. This is with the ADDed Talon Tune Heavy Spring. Notice how the sweet spot seems to be at only "2.25 to 2.75 Turns IN" on the hammer spring adjuster from backed out against the stock. The MAX travel of the adjuster plunger is at 4.75 Turns Into the Receiver before the Sear will not catch in the cocking stroke.

The Variation at 2.75 Turns was very low at only 3 fps across 4 shots. There was essentially No Performance / Velocity Gain above that mark. The Total shot count at this Reg. setting from 300 Bar down to 175 Bar with the 580cc Bottle appears to be 45-50 shots.

I think one can conclude that 160 Bar is Not capable of pushing a 33 gr. ZAN any faster than 990 fps. I will take her to the range in this config. and see how the "AVS" 33 & 34 gr. slugs fly before making any more adjustments. More to follow after some bench time.

3/16/2024	Reg. Pressure 160
TALON TUNES NEW SPRING - 4.75 TURNS MAX. Possible	ZAN 33g. / .218 SLUG
4.75	985
4.50	985
4.25	980
4.00	980
3.75	975 - 989
3.50	984 - 990
3.25	977 - 981
3.00	977 - 981
2.75	981 - 984
2.50	978 - 981
2.25	980 - 990
2.00	972 - 980
1.75	967 - 979
1.50	955 - 981

 

[Keyman62421]

Usually I start with speeds on high 800"s and start shooting groups. Increase speeds until the group fights up. If your LONG ranging you may have to " finesse" for accuracy. I agree with accuracy is what your after. Although, you have to deliver the round on target.