Might have found my 25 Avenger regulator setting

[JimD]

I've owned a 25 caliber Avenger for a couple months but I just got it back from warranty repairs because it leaked 150-200 psi/day.  It doesn't seem to leak any more so I've been working on the tune.  When I first got it I let all the air out and set it at about 1500-1600 regulator setting.  I think I had it at 1500 initially and it drifted up a bit to 1600.  That gave me about 800 fps on JSB King 25.39 pellets and about 720 on JSB King Heavies, 33.95 grain.  I got high 800s on H&N FTT but also got big groups.  Both weight Kings shoot well.  But then I tried 25.4 grain FX and the groups are a little smaller than the same weight Kings. 

But that velocity is a bit low, consistent with the regulator setting.  So today I turned it up in a couple stages.  Going up to 2000 on the regulator got me a little over 850 fps on the 25.4 grain Kings.  The group size was small (3 shot at 33 yards less than 1/2 inch).  I turned the hammer spring in 1 turn and velocity did not go up.  So I turned it back all the way out.

I still wanted more so I tried to set it at 2200 psi but it is really a bit higher.  It seems to be at 2300 when the tank is below 2500 psi and 2400 when it is up over 3000.  I might not be reading it right, it is hard to see this level of change clearly.  But I am now getting over 900 fps (highest 909, lowest 899 with 1 or 1.5 more turns on the hammer spring) with 25.4 grain JSB or FX pellets.  King heavies are 820-833 fps.  That's over 45 fpe on the lighter pellets and over 50 on the heavies.  I think that is enough.  I have some JSB Knockout and H&N slugs on the way and I will try those before calling this tune my final for this gun. 

The group with the hammer spring all the way CCW was about half an inch.  I turned the hammer spring in a turn and got about 10 more fps, not much, and group was the same size.  But I decided to go up another half turn.  Velocity was almost exactly the same but the group was about half as big (0.3 inch).  Then I tried heavies and the group was about 1/4 inch.  Then three FXs went into about 1/4 inch.  That's as small as I have gotten at this distance with this gun. 

I also did some penetration shots in 50 lb/ft3 MDF and both the FX and the JSB heavy pellets went through 3/4 inch of MDF (I am shooting individual 1/4 inch sheets stacked about 1/4 inch apart so how many sheets were penetrated is fairly clear).  The heavies at the lower regulator setting went through 3/4 but the lighter pellets only went through 1/2 inch of MDF. 

I would also like to shoot both these pellets at 50 yards or more and I will probably retry the MKII heavies too plus the slugs.  But for now I will leave the regulator and hammer spring alone.  I will also test pellet and slug penetration in wet paper (glossy paper this time because that is what I have). 

I also have not decided sight in distance.  I wanted to get the heavies up around 800 because I checked with a ballistic program and it suggests at that velocity I could zero at 33 yards and be within 1/4 inch elevation from 15 to 36 yards or so.  So if I decide the heavies are best I will probably re-zero at 33.  But I think I can stretch the 25.4 grain FXs out a bit but I haven't checked the numbers yet. 

[Jbsjeep]

I finally got my Avenger .25 in February (ordered it in December). The weather has finally gotten a bit more comfortable and got to the tuning myself. Like you, I started low, around 1500 to 1600 on the reg, with the JSB 25.4 Kings, Hades 26, FX Hybrids in 26 and Nielson 26.8 slugs in .249. I also worked up to 2200-2300 PSI on the Regulator to a very happy 914 fps average for all four with a very small std. deviation. I found that in mine, the Hybrids didn't shoot as well as the Nielsons did. They hit well but the group was much bigger with the Hybrids. 8 Nielsons create one raged hole at 30 yards with no adjustments in aiming point between the two JBS offerings and the Nielsons. I'm quite happy about that as I switch on the fly for longer shots. The hybrids tended to be closer to 1.25" in the same conditions. I've found from time to time that I can get a hair more zip if I add half a turn to the hammer spring and don't have to constantly fiddle with the regulator and still get a solid 32 shots before I hit the regulator. I can take it to 40 shots for sure but usually don't.

I think it's pretty interesting that we came to basically the same conclusion for our purposes. I've noticed that many have the Reg up around 2700 or 2900 and have speeds around 825 to 860. Seems like a waste of air to me.

The Avenger seems to be a very stable, usable and reliable setup. I'm interested if the rest of your findings as you go along.

Cheers.

[DMR214]

I also ha e the .25 avenger and I'm set at 2300 psi reg setting. It creeps 200psi in about an hour and 2800 psi overnight. But I noticed I get 920s with almost maximum hammer strike. Lowered the hammer tension about 2 turns and I in 870s getting hole into hole at 30 yards all the way to setpoint. 2 magazine go from 4000psi to 3000psi, But today when it hit 3000psi it dropped to 850s. How long is the turn around on your warranty Jim, im sending mine in tomorrow hopefully it doesn't take forever.

[JimD]

They told me a couple weeks when I called for a return number but it really took about 5 weeks to get the gun back - fixed.  Cost $30 to ship it to them but with it back and working well the money and wait seem very worthwhile. 

I will be trying JSB knockout slugs and another H&N slug next week (both about 34 grains).  If either shoot well I will include them in wet paper penetration tests later in the week. 

At my current ~50 ft. lb tune the FX 25.4 grain and the 33.95 grain JSB pellets both shoot through 3/4 inch of MDF at 25 yards.  The 25.4 would not do that at the lower ~35 ft. lb tune. 

I have mine sighted in to shoot about a quarter inch high with the 25.4 grain and about a quarter inch low with the 33.95 grain pellets at 33 yards.  I plan to practice hitting the bullseye at 33 yards with both by holding a little higher or lower as needed.  But maybe it will group well with a slug and I will need to factor that in.  I'm interested in knowing if there is a slug it likes (and I will probably try Nielsen) but I'm not sure I see a role the slug will meet for me.  The hole a 25 pellet makes is easily big enough to take small game with zero expansion.  If I want to smack a pig in the head I think I will probably need to use a pellet to get enough penetration.  A little less drop and significantly less wind drift would be nice but unless the slugs shoot as well as the pellets I will probably just use pellets.  But I will test both and let the results decide it.  I think it was Baker airguns that shot 25.4 and 33.95 grain JSBs into ballistic gel and got 12 inches for the lighter pellet and 15 for the heavier.  More than necessary for small game but seem like it would be handy if I need to smack something a little bigger.