Building the $100 precharged pneumatic air rifle: Part 3
by Tom Gaylord, a.k.a. B.B. Pelletier
The PCP built on a Crosman 2100B chassis.
Today, we’ll start looking at the accuracy of the $100 PCP. This is the test that has concerned me most since we began this experiment. I knew that a Crosman barrel could be very accurate because of the success of the Benjamin Discovery. But the $100 PCP is a job we threw together quickly just to test the concept. And when I say “we,” I mean Dennis Quackenbush, of course. It isn’t fully developed. Will it shoot well or fail miserably? Today, we’ll find out.
Since this is a lash-up job, there’s nothing connecting the barrel to the reservoir. This is a real free-floated barrel, but that’s not a good thing in this case.
I discussed this with Dennis, who advised me to attach the barrel to the reservoir tube with JB Weld. I was concerned that if I didn’t get the barrel fairly straight, problems would crop up when I scope the rifle. The open sights are mounted to the top of the barrel, so they’ll stay aligned at all times; but the scope base is on top of the receiver. The barrel is separate from that, and that could present a problem.
Thankfully, I’m a highly skilled craftsman, as long-time readers of this blog know all too well. My solution was to install a precision shim between the barrel and reservoir to maintain separation, and then to attach the 2 parts with several strips of linear adhesive material.
In other words, I put a piece of cardboard between the barrel and reservoir tube and then wrapped both with Gorilla tape.
Naturally, I don’t expect the blog readers to be capable of skilled work like this. I’m just showing it to you so your repair center will have the information when they do a similar job for you!
Now, it was time to test the rifle. I shot only pellets, of course, and I decided to start at 10 meters with the open sights that came on the rifle. If I was testing a Crosman 2100B, that’s how I’d start.
Right away, I messed up and over-filled the gun on the very first fill. I’m not used to the needle on the gauge stopping at the 2,000 psi mark, so I went over and filled to about 2,300 psi. Thankfully, Dennis over-built this rifle, but I didn’t want to test that aspect! Nevertheless, the rifle was filled without incident, so I fired the first 10 shots.
Crosman Premier lites were the first pellets I shot because this is a Crosman rifle, after all. I’ve found that pellets and airguns made by the same manufacturer often do well together.
The first pellet landed to the right of the bull and about right for elevation. I left it alone and fired shot No. 2. Since the pellets were in the white, I could see them without a spotting scope (this was only 10 meters); and they were landing close to each other. I settled in and completed the first 5 shots.
I was so concerned that the pellets might walk as the pressure dropped in the reservoir that I photographed the first group after just 5 shots. Then, I photographed it again after all 10 shots were fired.
After photographing the first 5 shots I returned to the bench and shot the other 5. When I went downrange to change the target I was surprised to see that the final 5 shots hadn’t enlarged the group at all! This is not a common occurrence, and it made me think that I should re-shoot the Premiers with a correct 2,000 psi fill, just to be sure. But I decided to wait until the end of the test to do it.
The first 10-shot group of Premiers measures 0.726 inches between centers. As noted, that size was reached in the first 5 shots.
After the first group, I adjusted the rear sight to the left, to get the pellets striking inside the bull. Then, I fired the second group with RWS Hobby pellets. After confirming the first pellet did hit in the black, I didn’t look at the target again until going downrange to change it. What I saw was both thrilling and astounding. With open sights, the $100 PCP had put 10 Hobbys into a group that measures 0.534 inches between centers. This isn’t just a good group — it’s a great group when you consider that open sporting sights were used. Granted, I’m only shooting 10 meters here and the group will be larger when the distance increases to 25 yards, but will it be that much larger? I’ll be using a scope, after all. And maybe I haven’t even found the best pellet yet.
After this group, I adjusted the rear sight up one step. Since the next pellet is a heavy one, that would probably keep it is the same place.
H&N Baracuda Match
Although this rifle is producing only 12 foot-pounds of energy, I thought the H&N Baracuda Match pellets might work well. So, I gave them a shot. Ten went into a 0.855-inch group. That’s not terrible; but in light of the others, it’s not as good, either.
Air Arms Falcon pellets
Next up were the Falcon pellets from Air Arms. Ten of them went into 0.683 inches. Since this is a domed pellet, it may group better at long range than the Hobby.
I then shot a final group of Crosman Premier lites — this time with the rifle filled to just 2,000 psi. Ten pellets went into 0.615 inches, making the second-best group of the day, with Hobbys being the best.
The rifle’s pressure dropped about 800 psi for the 10 shots in each group. So the valve is far from optimum at this point. And the reservoir could stand to be a lot larger.
The trigger is the 2100B trigger. While it does have a long pull, I didn’t find that it caused me any problems. I think it should stay as it is.
The rifle cracks much louder than a Benjamin 392 on 8 pumps. Crosman could shroud the barrel, but I’m going to recommend they don’t. I want to keep the price of the gun down below $100. Let the people who buy them figure out how to quiet their guns. They’re going to anyway.
I’m going to address these next comments to Ed Schultz at Crosman. The $100 PCP tests out the way we both thought it would. You can see the shortcuts I took to stabilize the barrel for today’s test. I would want more than 10 good shots from a rifle like this. I would want at least 20 good, accurate shots of 7.9-grain Premiers going at 850 f.p.s., give or take.
I’m going to continue to test the rifle at greater distances, so there are more reports to come. But there’s no longer any doubt that this is a viable airgun.