Air Venturi Seneca Aspen .25-caliber precharged pneumatic air rifle: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Part 1

Seneca Aspen PCP
The Air Venturi Seneca Aspen precharged pneumatic air rifle.

This report covers:

  • Important links
  • Filling
  • Benjamin domes
  • Test 1
  • Discussion 1
  • Power
  • Back to 3600 psi
  • Test 2
  • Discussion 2
  • Power on low
  • Pumping effort
  • Trigger pull
  • Summary

Today we look at the performance of the new Air Venturi Seneca Aspen PCP. Before I get to that, though, I will remind you that in Part 1 of this report (the one on this .25-caliber Aspen) I showed the links to the first 5 reports on the .22-caliber Aspen. I’m not showing those links today because they will become too confusing. If you want to see them, click on the link to Part 1 of this report and they are all at the top of the report that comes up .

Important links

Those links are important to me because I am testing this .25-caliber rifle in the same way that I tested the .22. That test was ideal to discover the performance parameters of that rifle and it will do the same for this one. I expect to see differences today, but this test will tell us how the .25 performs, relative to the fill pressure. With that understood, I am ready to begin.

Filling

As I explained in the test of the .22, it’s easier and more controllable to fill this rifle with the onboard hand pump than from a scuba tank. I will watch the onboard gauge as I pump. The rifle was sitting right at the 3,000 psi that I put in a week ago, so again, it does not leak. To take it to the 3,600 psi max fill took 25 pump strokes. That means each stroke puts in about 24 psi. In the .22 each stroke was putting in about 30 psi, so this one is a little different. This gun also pumps harder than the .22 which I attribute to a break-in that the .22 had and this one hasn’t had. I will keep an eye on this as the test progresses.

I also found the pump head was relatively dry this morning before I started pumping, so I lubricated it with the silicone oil that was provided with the rifle. I had already lubricated the head in Part 1, so this came as a surprise. I will also keep my eye on the pump head as the test progresses.

Now that we are at 3,600 psi we are ready to start the test. Only a single pellet is needed for this, as we want all data to corollate. That’s good because, unlike .22 caliber pellets, my supply of .25-caliber pellets is small. And .25 caliber pellets come fewer to a package, which exacerbates things.

Benjamin domes

I selected the .25 caliber Benjamin domes, because I had almost two full tins. This pellet doesn’t have a name beyond Benjamin, but if I ran the company it would be called a Premier, because that’s what it looks like.

Test 1

The first test was run with the power selector set on high. Remember, I’m starting with 3,600 psi in the gun — according to the built-in gauge.

Shot………Vel……….remaining pressure after the shot
1…………752 (report is loud — 4)
2…………764
3…………768
4…………765………………….3000 psi
5…………759
6…………762
7…………750………………….2600 psi
8…………746
9…………737
10………..727………………….2200 psi
11………..722 (report got louder — 4.5)
12………..707………………….2000 psi
13………..694
14………..683
15………..664………………….1600 psi

Discussion 1

We just learned a lot about this rifle. First, there is no real power curve. Fill it to 3,600 psi and you get 9 to 11 good shots with more-or-less steadily declining velocity. The distance at which you shoot determines the pressure at which you have to stop, because if you continue to shoot your groups will elongate as the pellets start dropping lower and lower.

Why doesn’t this rifle perform like the .22 Aspen I tested late last year? That one reached optimum power at 2,000 psi when set on high power. The short version is the valve is not optimized for .25 caliber. It doesn’t hold or pass enough air for the larger caliber. Like most of the PCPs from Korea, it just uses all the air that’s available on every shot. The .22 rifle has a power curve that peaks at a much lower pressure, which means the valve has a performance envelope, rather than running wide open. This is neither bad nor good — it’s just how the .25 caliber rifle performs.

Power

We don’t have an average velocity for the first string of shots, but if I pick 760 f.p.s. arbitrarily, the 27.8-grain Benjamin pellet develops 35.66 foot-pounds at the muzzle. A heavier pellet will develop even more power, as this is a pneumatic, and pneumatics favor heavy pellets. That gives you a rough idea of the power you can expect. For comparison, the .22 developed just over 29 foot-pounds with a heavy pellet on high power.

Back to 3600 psi

Okay, it’s time to test the rifle on low power. And remember, the two power settings are absolute on this rifle. There is no in-between. Before I can test it again I have to fill the reservoir back to 3600 psi.

It took 25 pump strokes to go from 1600 psi to 2300 psi. Another 25 pump strokes took the reservoir from 2300 psi to 3,000 psi. And another 25 pump strokes took it up to 3600 psi. That’s 75 pump strokes to go from 1600 psi to 3600 psi, which is 2,000 psi of air. Or, looking at the string above, that’s 75 pump strokes for 15 shots, which is 5 strokes per shot. This .25 caliber Aspen uses a lot of air per shot and is probably better-suited to filling from a tank than by the built-in pump — at least for shots fired on high power.

Test 2

Test 2 uses the same test conditions as Test 1, except the rifle is now set on low power.

Shot………Vel……….remaining pressure after the shot
1…………577 (report is quiet — 2)
2…………574
3…………574
4…………567………………….3300 psi
5…………565
6…………570
7…………564
8…………567………………….3000 psi
9…………561
10………..561
11………..559………………….2800 psi
12………..560
13………..552
14………..551
15………..548………………….2500 psi
16………..549
17………..545
18………..538
19………..531………………….2200 psi
20………..528
21………..522
22………..516
23………..509………………….1900 psi
24………..504
24………..493(still quiet)..…….1700 psi

Discussion 2

This string was more puzzling than the first. We see almost the same drop in velocity as the high-power string, only this one takes longer to unfold. I didn’t expect that. I thought there would be a rise in velocity that would peak at some lower pressure, but instead the velocity just fell straight off like it did on high power. It just took longer to fall. You could argue that there are about 17 good shots when the rifle is set on low power, compared to the 9 to 11 on high.

Power on low

It’s easier to pick a velocity from the low power sting. I’ll take 565 f.p.s. At that velocity the .25-caliber Benjamin dome generates 19.71 foot pounds at the muzzle, which is respectable. The .22 rifle generated just over 18 foot-pounds on low power when shooting a heavy Kodiak pellet. That’s close to the .25, but remember that the .25 is shooting a medium-weight pellet in today’s test. A heavier pellet would gain another foot-pound at least.

Pumping effort

At the start of today’s tests it felt like the pumping effort was greater for this rifle than it was for the .22, so I pumped the gun back to 3100 psi and then pumped 11 more times. That copied the test I did with the .22 rifle that took 30 pounds of effort. I then measured the effort required for pump number 11 at 33 pounds. However, as I pumped it this time, it felt like the pump was breaking in and getting both smoother and easier. I bet with a few hundred more strokes on it this pump will be the same as the other one.

Trigger pull

The trigger is a definite 2-stage affair as the rifle came from the box. Stage one is short and takes 6 oz. Stage 2 is reasonably crisp and breaks at 3 lbs. 1 oz. The .22 trigger was single stage and missing its return spring. It broke at 3 lbs. 3 oz.

I adjusted the trigger to break at 1 lb. 15 oz. There is a hint of creep in the second stage pull that signals reaching the break point. That makes this trigger very predictable. Stage one is now just a little looseness in the trigger blade, with no more adjustment possible, so I think that is also where the two-stage trigger went on the .22.

Summary

At this point I’m going to tell you that the Seneca in .25 should be treated like a PCP and not a multi-pump. Too much work is required to refill it after just a few shots have been fired. That gave me a great idea about how to test the .22 as a PCP, which has been one of the holdups.

Once again I will say that the Seneca seems like an ideal way to break into the world of precharged airguns. You may want to treat the .25 as more of a PCP and less of a multi-pump because of the amount of air it uses, but the same convenience of having the pump built in is still yours. I sure hope it’s accurate!

26 thoughts on “Air Venturi Seneca Aspen .25-caliber precharged pneumatic air rifle: Part 2

  1. THANK YOU! REALLY enjoying the Seneca teaching’, research! I have purchased a number air guns, powder etc., over the last three years? Like BB I lost my wife three years ago! And she was a real part of my life, team shooting, gunshows, also an author etc. My escape has been to go back to airguns, powder all types, shooting daily! I don’t write much any more myself! I did alot of proofing for my wife, also she was a little older than myself as I am a little old then you BB. But! I am usually the quiet man! Not tonight! Thank you again and Semper Fi!


  2. An eight shot pcp ~40 fpe hunter with the convenience of the built-in pump, even with the 40 strokes effort per magazine, I think is worth it. Accurate and reliable it would be.
    Good morning to you all.
    Bill


  3. B.B.,

    I like it. It is fine as is and still a heck of a deal to enter into PCP’s. I think that some will not find 5-ish pumps per shot discouraging. Looking forwards to the accuracy testing.

    Good Day to you and to all,……….. Chris


  4. BB,

    When you consider that a multi-pump requires 8-10 pumps for one full power shot, this does not sound to be that bad, most especially as you can have a quick follow-up shot if you need it. I am not certain that the .25 will be as big a seller as the .22, though it would be a better game thumper if it is accurate.

    I do not see one of these in my “collection”, but I too have been won over to this being a good choice for one’s first foray to “The Dark Side”.


    • I was thinking the same thing. 5 pumps for 750ish fps each shot with .25 caliber? And the ability to just do a followup or three if presented puts this gun, and this kind of airgun, into a separate breed as tank/ext. pump or multipump pneumatics.

      It might have been done already, but how many shots within 10 psi at high power could one string together with five or so pumps between each? At low power? I mean if it hold air, why can we just leave it at pressure, topping off between shots and after a session for the same mechanic as a multipump pneumatic but more power per shot?

      It probably doesn’t take any more air to push the pellet out at high pressure as at low but I think it’s the pressure behind that air has the effect on velocity. Once you’ve got the resevoir of pressure you only need to replace the consumption per shot vs repressurizing vis a vis multipump pneumatics.

      Or these things work far differently than I’d approach it. Which is likely 😉

      -Brent


      • Brent,

        On low power the pressure is the same, but less volume of air is used. That is why the projectile is slower. The air has to fill the volume of the barrel at a minimum.

        For me this air rifle is really a no go as I have a compressor and a tank and two hand pumps and an antique multi-pump that I am restoring. For someone testing the waters of “The Dark Side” this is a great one to start with.

        With minimal pumping between shots it would be easy to maintain a constant pressure.




  5. For the effort required, I’d also consider something like the .30 Hatsan springer you showed off a while back.
    Even tho that was a custom job and cost more, that was a nice hunter too, it just need a helper to cock it.
    Dont know if there is a pneumatic multi pump that will get you 760 fps with .25 Benji domes on 10 pumps, so i would fill, shoot and top off with 5 pumps, that seems like a good deal for a hunter.
    Have a nice day, Rob


  6. BB,
    I saw one video of a young guy trying to test this gun and he would get excited and pump more than he intended for quality testing. What I took out of this that a young buck might not mind the pumping this gun any more than most kids did their first multi-stroke BB guns. And, this gun’s price makes it affordable for the young guy that would like a powerful PCP but doesn’t have money for tanks or compressors.

    One question I would like to have answered on these guns is: Is it easier to pump to a given pressure with the on board pump or a hand pump?

    Enjoyed the blog as always,
    David Enoch


  7. BB
    Nice info and how you presented it. It’s a different way of testing for the self contained HPA source for the gun.

    And just me but I have a good feeling a heavier pellet like the JSB 33.95 will help with the shot string and usable fill pressure. I bet it’s more accurate too.

    From what I have seen with .25 caliber pcp’s is they act different than .22 or .177 caliber.

    And when the time comes I’m thinking you will want to know to what the heavier pellets will do in the .25 caliber multi-pump pcp.



      • BB
        Increasing the striker spring should really pick this gun up. I think they got it tuned low.

        It might even give a wider powerband with the striker hitting harder. It will be able to handle a higher full fill and a lower ending fill. Then the heavier pellets should also use the air better when you find the right striker and fill pressure.

        Me reading between the lines right now. The gun should be a performer if it’s got a good barrel once you spend some time with the tune.


  8. B.B.,

    On the topic of .25 pellet selection being limited,….. is there any industry rumors of that expanding anytime in the near future?

    To further expound on the topic, the JSB classic dome style have always done best in all of my air guns. So,… gimmicky pellets being put aside,…. where is the next step on improving the classic dome? Do we look at the current plethora of .177 pellet (and somewhat less so, .22) offerings, for a peek into the “crystal ball” of what we may see in the future for larger calibers?

    Compared to .30 plus, I feel lucky to have what I have in .25 being offered.

    Chris



      • B.B.,

        Well,.. short of uniformity/consistency (which the super high end stuff is supposed have), aerodynamic testing would be next. Maybe BC testing does that, maybe not. I suppose it does. Get from point A to point B with the least amount of FPS loss, which in turn should give you the most predictable flight path,…. in general,… ish. 😉

        FX is/was doing testing to match barrels/guns to specific pellets (or) maybe the other way around?,… either way, a good thing. A start at least.

        While not familiar with, I am sure than many similar undertakings have been done in the fire arm bullet world/industry already,…. though not addressing the classic Diabolo shape us air gunners must deal with.

        I guess,… I what I am asking about is (science). Fatten the dome? Make it more pointed? Round the back of the head,.. or,.. make it concave? Front to rear weight ratio? Etc.,… to infinity.

        ** Is there not (one) scientifically proven/theoretical design that will do the best?

        To further add to my ramblings,.. add in barrel twist rate/tolerances/fps. A “can of worms” to be sure.

        If I had to guess,…. the best of the best are using (computer) models, with the best information/parameters being put in,.. and then tweaking the design here and there,.. and then hit “enter” and see what happens. Looks good? Make it.

        If I have not already put you to sleep/given you a head ache/have you scratching your head/laughing out loud, yet,… is there anyone that you are aware of that is taking a (scientific) approach to pellet development? Or,… is it just make it look different, put in a pointed metal tip, add or subtract 2 grains of weight,… call it something new and do a launch?

        Heck,… I gave (myself) a headache with all of that! 😉

        Chris

        P.S.,…. If you do not know,…who could you ask?


        • Chris USA,

          smh!

          “While not familiar with, I am sure than many similar undertakings have been done in the fire arm bullet world/industry already,…. though not addressing the classic Diabolo shape us air gunners must deal with.”

          With 25 caliber and above PCPs and hybrids I don’t understand why we airgunners continue to talk diabolo pelets.
          For the smaller calibers and non-PCP the pellet makes sense in that it retards the velocity by KILLING the BC with drag. The uses of high power PCPs almost call for the exclusive use of bullets to maximize ENERGY down range. There are way more shapes, sectional densities, drag numbers and functional features in bullets than pellets will most likely ever have. So why the call for what already exists?
          As an example I have a .25 caliber rifle (PCP) that generates almost 100 FPE with a 55gr bullet. The retained energy and accuracy at 100 yds is way more than I can ever get with any scientifically designed diabolo pellet and very likely much more accurate at that range and in real world conditions!

          shootski


          • Shootski,

            I figured that you would chime in with some well informed comment. 🙂

            The .25 Red Wolf does 50 fpe but also gets 70 shots per fill on high power. My .25 M-rod is similar in fpe, but not near as many shots. So,…. in those cases, the HN Grizzly is the only bullet shaped pellet and neither guns preferred them.

            From what I gather, the .25 must be in the 100 fpe range (+50 fpe) to use bullet shaped projectiles successfully. .25’s like that are more the rarity rather than the norm though. So, you see the quandary?

            Your comment on sectional densities and other factors was interesting as I thought that there is (more) variances in the appearance/shape of pellets compared to bullets, but I will trust your comment.

            So, if we are stuck with sub 50 fpe PCP’s and they do not shoot any/many bullet shaped projectiles well,… then it only makes sense to ask if the Diabolo design has been optimized in a scientific manner,…. which was/is the general question I was asking.

            Chris


            • Chris,
              From what I have seen, the ability of an air gun to be accurate with the bullet projectile has more to do with twist rate than FPE. That is why FX is offering slug barrels for their newest platforms.
              Gerald


  9. B.B.,

    I concur with your discussion point that this rifles valve is not optimized for the caliber/pellet mass.
    Test 1; you note that the report got louder at shot #11 about 2,100psi: I’m guessing here that it wasn’t hammer bounce that you heard but rather the valve spring/valve pressure combination allowing the dwell time to lengthen enough to exceed the pellet in barrel time. That can be addressed in a number of ways some will increase effeciency and other ways that will increase the power possible. The valve appears to be in serious need of a tune for the rifle to have repeatable performance beyond the first seven shots. A heavier pellet will (in my opinion) only make performance worse based on your test numbers above.

    This rifle is interesting!.

    I look forward to your accuracy testing and the vertical stringing beyond seven shots.

    shootski


  10. B.B.,

    If you have the time…
    A string of 5 shots on target: on high power, same Benjamin pellet, pressure 2,700psi maintained by pumping, please.
    I think you may find the rifle most accurate and probably easier to pump?

    shootski


  11. I love my.22 Seneca Aspen BB, thanks for the info on it. I have my hammer spring setting three turns out so it has power still, but I still don’t have to pump a bunch. I love the adjustability of this gun I shoot three shots pump it 12 or 13 times and shoot some more lol. You were right about them H&N Baracuda match 21 grain 5.53s they are tack drivers! I did the pyramid air 10 shots for $10 and my slip says the RWS hobbies 11.9 grain we’re going about 1050 FPS that’s about 29 foot pounds so the gun has power the hammer spring was set one turn out when I got it.



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