by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2

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

This report covers:

  • Not the accuracy test
  • Man plans…
  • Testing as a PCP
  • Filling
  • Mounting the scope
  • Sight-in
  • Back to 10 meters
  • Back to 25 yards
  • Scope adjustments
  • My test plan
  • First group of five
  • Shots 6 through 10
  • Second group
  • Third group
  • Discussion
  • Summary

Get ready to learn something, kids, because school is in session!

Not the accuracy test

Today would normally be the start of the accuracy test for a normal PCP air rifle, but the Air Venturi Seneca Aspen PCP is anything but normal! I did shoot a lot of targets today, but there aren’t going to be any dimes in the pictures. I was just trying to figure this rifle out!

Man plans…

I figured I would mount the 4X32 AO scope that comes bundled with the rifle and at least start to shoot for accuracy. Well, there is a saying about thoughts like that. Man plans and God laughs! If you don’t believe it, read the book of Ecclesiastes. It was written by King Solomon, who was the wisest man ever to have lived. Near the end of his life he figured out the meaning of life and boiled it down to just that. Oh, he didn’t say it that way — he was more reverent and polite about it, but in chapter 12, verses 12 through 14, he pretty much sums it up that way.

Testing as a PCP

Although the Aspen is a PCP, I have never tested it that way. It also has a built-in air pump and when I tested the .22 I always pumped it, because I learned it liked much lower air pressures than the reservoir was built to contain. So, I thought, why not just pump it and I can be the regulator? It worked like a charm, if you can recall those tests.

But we learned in Part 2 while testing the velocity of this .25 that it likes much higher pressures. So, this was the perfect time, I thought, to fill the rifle from a tank and use it as a PCP. My plan was to sight in and then shoot some groups at 25 yards to discover the best pellets and also whether high or low power was best. And, that was when the laughter started!

Filling

I connected the fill probe to the rifle and filled to 3600 psi/250 bar. Let me warn you — the reservoir fills very fast. Go easy on the air tank knob until you learn the rifle or you will have to bleed it down. It may be capable of shooting at higher pressures, but it may not want to. In fact — it doesn’t.

Mounting the scope

The next step after filling was to mount the scope. As long as the rifle comes with a scope, I at least need to try it. The two-piece rings have two-screw caps so there is no trick to tightening them. I did shim under the rear of the scope with one thickness of credit card simply because 75 percent of the air rifles and firearms I have ever scoped need some kind of downward slant. If you put a shim in and they don’t need it you do no harm — you just get a little more elevation adjustment. If you need it and don’t have it you have to remount the scope.

Seneca Aspen PCP scoped
I mounted the 4X32 AO scope that comes with the Aspen in the rings that are also bundled.

Sight-in

I decided to use the single shot tray today. That allows me to switch pellets at will, although the need for that never arose because this is where things got strange. All testing today was done with the Benjamin dome. I always start by sighting in at 10-12 feet from the target. That eliminates any surprises later on.

I began shooting on low power. The thought was I would then switch to high power when all the pellets had been tested on low, but the laughter started to increase. You’ll see why in a bit.

The first shot (shot 1) hit below the target paper, but at 12 feet you expect it to be low. In fact, it would be at least as far below the aimpoint as the center of the bore is below the sight plane (the center of the objective lens). My first shot was just a little below that and a little to the right. Thank goodness for the shim!

Back to 10 meters

A second shot (shot 2) hit very close by, so I raised the scope several clicks and also dialed in some left adjustment. The third shot (shot 3) hit a little higher and over to the left. It wasn’t quite centered but was close. Close enough that I backed up to 10 meters and fired again. This shot (shot 4) was higher but still not high enough. It was also over to the right again, so I increased the elevation and dialed in a lot of left adjustment. The final shot at 10 meters (shot 5) was at the bottom of the target, but too far to the left. I then adjusted the scope way up and way back to the right. At this point I felt comfortable to move back to 25 yards.

Back to 25 yards

When you move from 10 meters to 25 yards your impact point will rise without adjusting the scope 95 percent of the time. At least mine does. It rises by an inch, so I factor for that when sighting-in.

The first shot from 25 yards (shot 6) hit just outside the black at 1:30 position. Now I was at 25 yards, so the adjustment clicks move the impact more. Each click is 1/4-inch at 100 yards, so 4 clicks are 1/4-inch at 25 yards. I dropped 4 clicks and went left 4 clicks, which should have put the impact into the upper right quadrant of the black, but instead, shots 7 and 8 were very close to the center of the bull. In retrospect I should have fired another shot, but these two were stacked so I felt I could begin shooting a group. Ha!

Aspen sight-in
Here is the sight-in target described in the text above.

Scope adjustments

I will mention here than the scope adjustments seemed to move the impact point of the pellet exactly as they should. There was no stiction of the reticle remaining in any place after it was adjusted.

My test plan

I thought I would shoot pellets until the rifle started dropping them below the aimpoint, which opens the group. Of course I will do this on both power settings with all pellets, so there is a lot of shooting to be done. I will take a picture of the group after every 5 shots.

Let’s see, I’m shooting on low power and I have already shot 8 shots on the fill. The tank still reads about 2900 psi, which should be good enough for some more shooting, so I continued, hoping I was right about the pressure.

Aspen pressure
After sight-in that was 8 shots the Aspen’s pressure gauge looked like this. I read it as 2900 psi.

First group of five

And I watched the first shot curve through the scope and land almost two inches to the left and above the center of the bullseye! Okay, I’m here to learn about the rifle. Let’s keep shooting.

Shot number two hits to the left of the first shot. See? I was right! The shots are walking to the left and towards what I thought was the aimpoint. Shot three hits a little to the left of shot two and now there is a line of three holes that is walking down and to the left — towards the center of the bull. Oh, what a smart boy am I!

Aspen first group 5
I marked shots 1 through 3 in this group of 5, so you could see how they walked toward what I thought was the established impact point. Shots 4 and 5 didn’t bear that out.

Okay, so maybe I wasn’t right about where the point of impact was after all. Or maybe the rifle wants the pressure to go even lower? So back to the bench I went and continued shooting at this same target. Surely this time the shots will walk into the center of the bull.

Shots 6 through 10

This time I just shot and didn’t pay any attention to where the pellets were hitting. Unfortunately I could see all of them through the 4-power scope, which is my way of telling you that, besides the adjustments working well, this little scope is also pretty clear. But, darn it, the shots just weren’t going where they were supposed to!

Aspen first group 10
There are the five new holes and I don’t know what to tell you about them, except they aren’t where they are supposed to be! I saw none of them in flight.

Second group

The gun is still reading in the mid-2500s, so I continued shooting. I adjusted the scope to the left a couple clicks but left the elevation alone. The first five pellets are closer to the center of the target, but they are also a little lower.

Aspen second group 5
The group has moved left, but the shots are starting to fall lower. I want to shoot 5 more to see where they go.

I shot the next group of five and didn’t see the group grow much, except for a flier that went low and right.

Aspen second group 10
The second five pellets did not continue to fall like I thought they would, but one veered off low and right. The others are actually as high as the first 5.

Okay, the rifle isn’t doing what I thought it would. But one thing is certain at this point — it’s out of air. It has to be because the gauge shows 2100 psi and in Part 2 we saw it drop from 2000 psi pretty rapidly. There is not enough air left for another 10 shots, so it’s time to fill her up again. I filled to 3000 psi, because I thought that would give me the most consistent shots.

Aspen pressure low
After the sight-in that was 8 shots plus the 20 shots I just fired for record, the Aspen’s pressure gauge looked like this. I read it as 2100 psi.

Aspen filled
I filled the rifle to 3000 psi.

Third group

I left the scope where it was and tried my best to shoot the best group I could this time. The first shot went to the same place the rifle had been hitting. Then shot two dropped about one inch. WHAAAAT??? Had the pellet hit the muzzle cap on its way out? Is the Benjamin dome not the right pellet for the Aspen? I completed the group with the same care as the first two shots and got a reasonable group — except for the one flier.

Aspen third group 5
After filling to 3,000 psi again, here are the first 5 shots. Shot two is the low hole. I could live with that upper group.

Okay, I have a good group of 4 and one flier. What’s going to happen with the next five shots? Actually, the group did grow, but not by as much as I expected. Have I gotten a hand on the Aspen .25 shooting the Benjamin dome on low power?

Aspen third group 10
The pellets stayed together this time.

Discussion

I know the pictures are fuzzy today. I had to enlarge them too much for this article. But they do show the progression of my work — which took a LOT LONGER than I thought! Remember, this isn’t the accuracy test. It’s B.B. Pelletier learning how the .25 caliber Aspen likes to shoot.

I can hear someone right now, “BB, are you sure the Benjamin dome is the most accurate pellet for this rifle?”

No, I am NOT sure. In fact, I have no idea. It might be the worst pellet. I had to start somewhere and after I got into everything you have just read I sure did not want to add another variable to the mix.

I wanted to shoot other pellets today. I also wanted to shoot on high power. But until I knew something about how this gun prefers to operate, anything else I did would be suspect. At this point I think I have established that this Aspen wants to shoot at 3,000 psi or slightly less when it is set on low power. I need to confirm that with other pellets, but given what I do know, that test should go faster and smoother.

I am curious as I can be about how it does on high power. I hope to get to that real soon.

I know that I will test this .25 Aspen as a PCP, rather than as a multi-pump. Too much work is required to operate this one for me to be pumping all the time. That doesn’t mean it doesn’t work well as a multi-pump. Hunters should find it especially useful that way.

You guys also want me to tweak the power adjustment (the screw in the back of the action). Most of you just want to know how powerful it can be. I will go there once I know the gun better.

Summary

I always say that a rifle with many adjustments presents an infinite list of possibilities. The Seneca Aspen is one such air rifle. I can never test everything, so my goal is to demonstrate its potential in a useful way so those who are interested can make a good decision.