Building the $100 precharged pneumatic air rifle: Part 1
by Tom Gaylord, a.k.a. B.B. Pelletier
Airgun manufacturers: If you read this blog, today’s report is one you’ll want to pay attention to! When I announced last Friday that I would be writing this, I received more interest than any subject that’s ever been raised on this blog. That makes this a subject of primary importance to anyone who wants to know what the consumer wants.
Blog readers: Many of you have not read or perhaps not understood all that I’ve said about this project. I am therefore going to explain it now in clear terms, so that everybody will know what I’m talking about. This project is a proof of concept. It is not a new airgun that’s about to be built. I don’t know if it will ever be made; and if it is, it probably won’t look like what you’re about to see. This is a single airgun that incorporates the features I’ve envisioned in a PCP that could retail for less than $100. A lot less, if you follow carefully.
The base gun used as the starting point for the project is a Crosman 2100B. That’s a multi-pump pneumatic that has a lot of plastic on it and a soda-straw barrel. It’s one of those dual-ammo rifles that shoots both BBs and pellets but has a rifled bore. As this report is written, Pyramyd Air has them priced at $59.95.
Dennis Quackenbush turned a Crosman 2100B multi-pump into a PCP by adding a reservoir where the pump mechanism used to be.
The forearm tip no longer has anything to attach to. It used to be the anchor for the pump pivot.
To convert the rifle, Dennis had to remove the multi-pump mechanism (pump linkage, pump anchor, pump head and rod and connecting hardware), including the tube that houses it. A steel hydraulic tube was installed in its place. Dennis chose SAE 1026 tubing that’s 0.75″ diameter on the outside and has a wall thickness of 0.083 inches. That gives the tube a burst pressure rating of 14,386 psi — more than enough for this project. In fact, to use Dennis’ words, it’s overkill.
A tube with a thinner wall thickness would have more internal volume, but it would be marginal for the threads that Dennis cut inside the tube to attach to the brass firing valve. Thinner tubing would have to be pinned instead of threaded. It would still work fine and the burst rating would still be many times the expected operating pressure.
To complete the gun, Dennis had to thread the other end to accept a fill nipple. He also had to change the firing valve return spring because the thick-walled tube didn’t allow sufficient clearance for the factory spring.
Cost to build
What are we looking at? The gun costs $60. The new reservoir tube has a nominal cost of $10. The fill nipple has a small cost, along with some other small parts. And Dennis has to get paid for his time to remove the factory parts, thread the new tube on both ends, install the new tube and seal it on both ends. He also had to turn the pump arm that swings into a forearm that attaches to the pressure tube. A special barrel hanger had to be made so he didn’t need to drill and tap holes in the pressure tube. Takes about a minute to write about all the work and maybe 6-8 hours to do it. Do several and you’ll find ways to shorten the time to perhaps 4 hours.
So — those who expect Dennis to go into business making this airgun want him to fork out $75 and spend 4 hours of his time to make $25. Does that seem fair? Of course not! Even if he could cut a deal with Crosman or a distributor to lower his out-of-pocket expenses for the starter rifle, he’s still working for peanuts.
Crosman, on the other hand, could do something like this with great efficiency! They could make small adjustments to the manufacturing process upstream, so this gun wouldn’t cost them any more to build than the 2100B — or if it did cost more, the difference would be quite small.
So, why don’t “they” do it? Well, I expect our comments will provide some answers. For starters there will be those who find plastic on airguns to be poison. No plastic for them! And the soda-straw barrel will also turn them off. What are “they” trying to foist on us? Don’t “they” know that plastic and cheap barrels turn us off?
Well, I’m not doing this project for people who feel that way. This is a precharged airgun that can retail for less than $100, and corners have to be cut. We don’t ever skimp on safety, but performance? Forget performance! You’re going to get a soda-straw barrel and lots of plastic for under $100, and you’ll be happy with it.
Believe it or not, there are a lot of shooters out there who would be thrilled to get a PCP for under $100. They would accept the thin barrel and the plastic, knowing that this is the only way they will ever get close to their goal of an affordable PCP. Those are the ones I’m doing this project for. The others can buy the more expensive PCPs and make all the comparisons they want.
Is such a PCP worth the effort? What kind of velocity will it have? What kind of accuracy? How many good shots will it have per fill? Is it an airgun worth having, or is it just a dream that was poorly executed? We talk about these things on this blog all the time — but today, thanks to Dennis Quackenbush, we actually have one we can test.
I thought you readers would really enjoy the rifling twist-rate test I did this year and last. I published 13 parts of that report; and by the end of it all, I was standing alone in my field, listening to the crickets chirp. I also published the entire test in Shotgun News as a feature article and, while the editor got excited along with me, there were more crickets chirping. It’s clear that I don’t always know what will turn your crank.
However, if the comments that came in when I merely mentioned this test was coming are any indication, many of you are very interested. And now you understand what this is.
This gun has a cheap soda-straw barrel (one made from very thin steel tubing). It’s rifled with a compromise rifling that’s good for both lead pellets and steel BBs. The trigger is the same one that’s on the Crosman 2100B that I tested for you. So, expect accuracy like you saw in that test. It wasn’t that bad, as you will see, if you bother to read that report. As for velocity, well, I already know what it is, but I’m not telling today. That will come in Part 2, like it always does.
The point of this test is to see if a gun can be made this way, and, if it can, how will it perform? I’m not going to tune this rifle to turn it into a viable air rifle, if it isn’t one already. I just want to know if it works. If it does work, does it work good enough that it would be worth building a commercial rifle just like it? In short — is this worthwhile?
I haven’t mentioned numerous things. Things like the fact that larger-diameter tubing could have been used, if the design was altered upstream in the manufacturing process. The cost wouldn’t have been that much more because the alterations would have been made with cost control in mind. Obviously this rifle could also be made as a .22. Is that of interest to anyone? There is a Crosman 2200, you know. A better trigger could be made if there was corporate support for one.
I also haven’t talked about the obvious point that the fill pressure of this gun will be lower than even that of the Benjamin Discovery. Because of that, the wall thickness of the pressure tubing can be much thinner than what’s been used here, meaning a production rifle could hold a lot more air than this one. So, whatever shot count we see here can easily be increased with very little additional cost, if any.
And the valve can be modified by an engineer to work best at the pressure that’s available. The new valve will be different than the one in this test rifle, but it doesn’t need to cost any more money.
In short, I’m testing a concept — not a production air rifle. The final rifle can be so much more than the one I test for you, yet the cost to produce can easily be held in check to ensure that a retail price of less than $100 is entirely possible. I’m tired of being told by airgun companies why something can’t be done, and now Dennis Quackenbush has made it possible that I don’t have to. None of us do.
But this is not a high-quality air rifle that’s made of wood and steel. You can’t build a PCP for under $100 and have those things. This is an air rifle for those guys who want to try out PCPs but don’t want to spend large amounts of money getting them. And also for guys who just don’t have the money to spend — period. That doesn’t mean that it has to be inaccurate — but don’t expect a Lothar Walther barrel. And accept plastic for what it is. You accept it on Glocks — expand your horizons.
This project promises to be quite interesting. It will answer questions I’ve wondered about for close to a decade. Because there’s a real air rifle to test, it will put an end to all the loose discussions and blue-sky dreaming that goes on…because this rifle now exists!
I’ll end with a thought from Dennis. If this rifle is worth making, then a lower-cost hand pump (that would fill only to a lower pressure) would also be extremely good to have. He’s thinking about that one right now.