Umarex Air Javelin airbow: Part 4
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- More to test
- What are the holes for?
- Remove the old 88-gram cartridge
- Lots of gas!
- Install the adaptor
- Cock the gun!
- Don’t do as BB does!
- Adjust the dot sight up
More to test
I didn’t tell you this but I asked Umarex to send me a 12-gram CO2 adapter so I could test the AJ with 12-gram cartridges. Some readers had asked about that possibility and since Pyramyd Air doesn’t carry the adapter, I went straight to Umarex.
Let’s look at how it works. One end has an end cap that unscrews to accept the two 12-gram cartridges. The other end is treaded to screw into whatever airgun you install it on.
The adapter has an end cap (arrow) that comes off to insert the CO2 cartridges, and threads on the other end to screw into the airgun. The holes are for moving the end cap when pressure holds it tight.
The two cartridges go into the adapter nose to nose. The piercing end of the first cartridge goes in first and the piercing end (small flat end) of the second cartridge is left up at the top, where the pin in the cap can pierce it. There is a spring-loaded winding tab on the cap. The spring holds the tab flat against the cap until you need it.
No directions for use came with the adaptor but it is pretty easy to figure out. I unscrewed the end cap piercing screw as far as it would go before dropping two cartridges inside. And I dropped in 5 drops of Crosman Pellgunoil before inserting the first cartridge. Then I put more Pellgunoil on the tip of the second cartridge.
What are the holes for?
If you ask what the holes in the sides of the end cap are for you haven’t yet encountered a gas gun with so much pressure that it wouldn’t let go of the end cap. This used to be a real problem in the 1950s and ’60s when improper o-ring material would swell from the gas and no let go of the end cap for hours after the gun was empty. With modern materials there is no more problem, unless the gas pressure inside the adapter is still high. This is not a large problem; it’s more of a convenience.
As you can see, I unscrew the piercing screw on the end cap as far as it will go, then screw the end cap down as far as it will go. Now I pick up the spring-loaded tab and start screwing the piercing screw in. That one screw is piercing both cartridges. It pushes the bottom cartridge down on the internal piercing pin inside the adapter as well as screwing in the piercing pin in the end cap. So I run it in as far as it will go. I heard no gas escape when I did this, but just to make certain the piercing pins were out of the way of the gas, I unscrewed the tab about a turn.
Remove the old 88-gram cartridge
Before the adaptor could be installed I first had to remove the previous 88-gram CO2 cartridge that was in the AJ. I didn’t know for sure but I calculated there were around 20 shots on it. We learned in Part 1 that the AJ has up to 30 good shots on one 88-gram cartridge. The last shots will send arrows out at just under 200 f.p.s. while the first shots have them going over 300 f.p.s. I will have more to tell you and show you later in this report, but for now you need to know that I was removing a cartridge that had a good 10 shots remaining inside. I had to do it to get a shot count from the two 12-gram CO2 cartridges in the adapter I’m about to install.
Lots of gas!
I will say this. Once you slowly unscrew the CO2 cartridge it comes to a point when the remaining gas is no longer sealed and starts hissing out. That lasted a long time — several minutes at least. I also dry-fired the AJ about 10 times as it was loosing gas to speed up the process. In the end the last gas hissed out and the old cartridge could be removed. The gun was now ready for the adapter.
Install the adaptor
The adaptor just screws into the gun where the CO2 tank was. Remember I put Pellgunoil inside when the cartridges were pierced, so that gets blown into the AJ to get on all the internal seals. BUT…!
Cock the gun!
Umarex tells you not to cock the gun when installing a new cartridge and I expect they also mean this adaptor. That is obviously a safety issue. But the adaptor holds two 12-gram cartridges that have limited gas. So I screwed the adaptor in, and when the hissing began I cocked the AJ and stopped it instantly.
Don’t do as BB does!
This is an object lesson. Some of you think I am modest, but the truth is — I am often that bad example your mother warned you not to follow! I set up the target bag in my back yard about 10 meters from the shooting bench. Yes that’s pretty far but I hadn’t shot the AJ in two months and my last recollection was one of great accuracy. It really was accurate last time — what could go wrong? I held the red dot in the center of the target that was taped to the bag and fired the first arrow. But I couldn’t tell where it went. It wasn’t anywhere on the bag! Oh, oh!
I looked in the grass all around and under the bag for signs of the arrow and then in the wooden fence between my property and my neighbors. Nothing. So I dragged the bag back to 5 meters and shot again. This is where I should have placed the bag to begin with.
Adjust the dot sight up
This time the arrow hit the bag, just below the bottom of the target paper. My previous shot had been taken at twice the distance, so the lost arrow is definitely somewhere in my lawn at something less than 10 meters. I searched for another 10 minutes for that first arrow with no luck. Umarex had only sent me three arrows with the AJ, and now I was down to just two. I adjusted the elevation up considerably and shot again.
Shot three hit a half-inch or less from shot two. It was on the bag but still below the target paper. From the looks of it (it was on an angle in the bag), it may well have hit the back of the second arrow— something I would discover in a little bit. Now I knew I was on the target so I cranked in a whole lot more elevation and moved the bag out to 15 meters.
Then I let fly with shot number four. This time the arrow hit the bottom of the 6-ring, almost touching the bullseye at 6 o’clock. Wow! I pulled the arrow out and moved the target bag out to 20 meters.
That shot had looked so good that I fired my second shot (number five on the CO2 adaptor). It hit the target about 3/4-inches below the last one. I needed to watch out or I would Robin Hood my two remaining arrows.
The last test in Part 3 demonstrated that the AJ is very accurate at this distance, so I felt confident it would not be a problem. However — remember that arrow that may have been hit in the back? I knew that I would nail the target in line with the center of the target and with luck I’d be inside the bull. No such luck! This time I heard a sickening sound of the arrow hitting the fence behind the bag. I have never missed the bag before this shot and was surprised I missed it this time. I found the arrow that had gone 4 feet wide to the left and was halfway through the fence.
When I pulled that arrow out of the fence I examined it to see why it had gone so wide. Right away I saw it. The end of the arrow is blown out on one side. I think I did hit the back of this arrow earlier and now I was rewarded with a wild shot. When I enlarged the pictures of all three arrows that was taken before the test started I saw that none were damaged this way. That is what I meant by that earlier picture being so fortuitous.
The end of the AJ arrow that went so wide at 20 yards was broken out on one side — causing the arrow to veer to the side as it came off the end of the air tube. This arrow was probably hit in the rear on shot number three.
For safety’s sake I moved the target bag back to 15 meters and fired my one remaining arrow three more times — shots 7, 8 and 9. Shot 7 hit the target at the bottom center of the largest ring in the white. I had to pull the arrow to shoot shot 8 and it hit the target about 3/4-inches below and to the right of shot 7. On this shot I noticed a lot of time between the shot and the arrow hitting the bag.
I pulled the arrow and fired one more time. This time there was a definite slowing of the arrow and it hit at the bottom of the paper, a little more than an inch below shot 8.
Based on this test I can say that two 12-gram CO2 cartridges give you about 8 good shots. They are not all the same speed, but I believe they all fall within the velocity spread of the 30 good shots you get from an 88-gram cartridge. Analyzing the costs tells me you get 8 good shots for about $1.00 with two 12-gram cartridges, and 30 good shots for about $8.00 with one 88-gram cartridge. The advantage of the adapter is shots that cost less. The advantage of the 88-gram cartridge is a lot more shots per cartridge. The velocity of the shots is the same because CO2 varies its pressure due to temperature. Volume is not a factor in pressure.There is no easy way to increase or decrease that pressure — certainly not one that’s available to the field.
The second thing I would tell you is to always examine your arrows just before loading them. I didn’t and only through a fortunate photograph was I able to determine that an arrow had been damaged during this test. A damaged arrow flies erratically and is too risky to shoot.
One last comment is that I need to jack up the rear of the dot sight for the next test. I had to apply too much elevation to get the arrows near to the aim point.
I’m still very impressed by the Air Javelin. Even with the challenges of today’s test, which in retrospect were all mine, the AJ held its own. When it is given half a chance it places its arrows close together at the distances I have been testing.
The CO2 adapter performs as well as many expected. I was surprised by the number of good shots we got in today’s test. And it is very easy to set up and use.
Hopefully we will see the AJ at least once more, and this time with more arrows and no sighting problems.