back to db page

Classic Reservoirs

I've had a R+D project running for several years: that of Classic Reservoirs. I've seen a few - examined a few - talked to owners, and read everything I could find regarding specs. and usage.

Everybody's classic reservoir is the "Ball or Globe" reservoir. Everyone also knows all the stories of them being fragile. They were made of copper, brass, even iron. Sorting out the fact from the legend is always part of any re-creation project.

I've been asked, since day one, to make "faithful reproductions" of all the wonderful old classics. And, many of them were wonderful at that. But, many things have changed in the past 200 years. We behave differently and expect far, far more.

Most historic PCP reservoirs were made of sheet iron - wrapped, riveted at the seams, and then brazed to hold air. Most air cane reservoirs were also made this way. I've measured some of the sheet iron at only .030-.035" ... that's thirty five thousandths of an inch thick. Pretty thin ... and we're not talking about modern rolled sheet steel either. We're talking about a decidedly lesser product of vintage manufacture. I've always found it curious that so many people seem to feel comfortable taking a reservoir made to hold approx. 500 psi, and now (200 years later!) filling it with CO2 - which can reach 1,200 psi on a hot day). Not me.

Everybody loves the old classics. But - most of them are broken and/or frail. Some shoot them off of Co2, right or wrong. Some spend money to have the reservoirs tested ... some evidently take chances. Obviously ... I won't take any chances. And, I can't make a product which will just barely get the job done. It has to have many safeguards built into it, and it needs to satisfy the expectations of modern performance (or nearly).

One of the banes of my work is the public fascination with light weight rifles. This mostly comes from a total lack of understand as to how a PCP develops it's power and the machinery required to make a PCP do so safely. A firearm can be very light - just stick a bullet in the chamber with more powder in it ... whoo...lahhh!! More power. Simple. Now, why do we fuss so over PCP's and make it all sound so ... well ... complicated? ha ha. Mostly; it's because ... it IS complicated. Good folks simply do not realize that they are comparing apples to oranges when they tell me that so and so sells (or did make) a nice light weight PCP. (Just so happens it's 1/4 to 1/2 the power of mine ... but, hey ... that shouldn't matter ... right?). Well ... it does, yes. It makes all the difference. Yeah - I can make a light little "Pop Gun". But everybody wants more.

So, when approaching the subject of "Classic Reservoirs", I had to proceed with extreme caution. I had to research materials and alloys. I had to gather the appropriate math and examine each design from the perspective of material specs, geometry, areas, volumes, and pressure. And, whereas the historic examples benefit from legend having rewritten their capabilities in myth, mine would need to actually perform to disclosed specs.

I also had to develop a process to test the prototypes and proof test the pressure vessels. OK, that's some of the background. Let's get to some pics.

Prototype Ball Reservoir and Cone Butt Flask from Barnes.

Several layers of safety have been built in. First, in the choice of alloy. Secondly, in the geometric design of the component parts and their internal construction. Thirdly, in the addition of a bottom O ringed cap - designed so as to prevent excessive overfill. Fourth, in the addition of a regulating overfill prevention valve. Fifth, in the addition of a quick fill provision.

Final dress would see these covered in leather as were the historic pcs. Each features a regulating overfill valve.

Special tooling had to be built and special equipment had to be purchased and assembled in order to test the structures.

Please note the quality of this weld. Only special equipment, special jigs, special alloys, extreme attention to detail, and many years of experience produce work such as this.


And the proof is in the numbers. Both of these test units were proofed to 5,000 psi.

Keep this in mind. This DOES NOT MEAN that these reservoirs would be approved for such a working pressure. Far from it. I show you this only to show the extremes this program has gone to to produce a safe product. Several layers of prevention will be in place to prohibit overfills. However, I'm testing for the worst case of cascading screw-ups.

There will be two classes of classic reservoir designs. One will be a lighter weight design exclusively for CO2 use. It will have a resetting, regulating overfill prevention valve which I will set and fix at approx. 1,100 psi. It will be my intention that these valves never be tampered with. Anyone who would seek to do so would be simply ... stupid.

The second class of classic reservoir designs will be for my medium pressure PCP's and be regulated to approx. 2,000 psi. This will allow for classic appearance with modern performance.

There will be much more on this subject as I develop this area of my work. Anyone will be able to see that this is the critical technology required to produce any and all PCP's which have ever been built. And, to do so responsibly.

In closing ... let me tell you a story.

I bought a used Jeep once. Nice V-8 Renegade. I was happy. I hoisted myself into the bucket seat and smiled. On the way home, I listened to the gentle flapping of the soft top, the hummm of the mud grip tires. I shifted the spunky stick and felt the V-8 pull. Ahhh ... life was good.

Then I started noticing that "flapping" alittle more all the time. And, when I'd get out, that rounded hump of a metal door sill would catch on my wallet and flip it out of my hip pocket in a little game we liked to play. And, ya know ... that tire "humming" was really more of a "drooooooooning" ... wasn't it?

Determined to be happy, I told myself that (given the thirty-five pound clutch release) I sure was glad it was only a three speed stick! Maybe covering that raw steel floor in the back would allow me to actually haul a bag of groceries without denting the cans so much, but; that ... FLAPPING was starting to get on my nerves a bit.

Well, the new Michelin snow grips really got rid of that endless "ROARING" of the tires ... but; surely this heater was someone's idea of a bad joke. Roads which I'd never even noticed before had all of the sudden completely gone to ruin as I bucked and leaped around my daily circuit. And this INCESSANT FLAPPING really was a BIT MUCH now!!!

About the same time as I realized my wallet was under the gas pedal ... again, I bounced across the left turn arrow painted on the pavement. Fortunately, my head did little damage to the roll bar when it rebounded off the foam padding. I couldn't hear the "thud" because of all the FLAPPING. I do recall though, thinking how awkward it was to get my left foot about 10" off the floor and onto the clutch petal while wrapped in a lap blanket to keep frostbite to a minimum. But, so long as the can of de-icer held out, I could reach through the plastic flap and occasionally spray some onto the windshield. I'd get home.

The moral of the story is, be careful what you wish for.

Everybody wants that faithful reproduction of the Lewis and Clark PCP. You would have to screw off the butt flask every time you wanted to charge it ya know. Sure - and that means threading it back on each time too. Now, that long twist barrel won't give you the MOA @ 50 yards that everyone expects, but ... hey ... it'll be fun. You'd rather have the brass barrel than a chrome moly steel now ... right? OK, and 500-600 fps will suit your expectations I trust? Hey - we don't have "Magnumitus" ... do we? Now; this reservoir again, I'll have to find some old thin iron sheet and braze one up for you. Now, don't ya dare overfill that thing ... no MIG welding on this project ... (he he) ... this is pure history. Those sights should get you on paper at 20 yards, so long as you aren't over 40 (Lewis and Clark were not ya know). Ya keep your nose out of the bore when muzzle loading it now ... ya hear. Two stage trigger ya say? ... good one ... right!! ;?)

Yes, I will make a version of the L and C rifle. No, it won't be a faithful reproduction. Because I'd never hear the end of the complaints after the dream phase wore off. I know there's many who just want a Franklin Mint version to hang on the wall. But, I don't make that type of product.

What I make will first be safe. Then accurate. And dependable. And, it will be a Barnes PCP.

Details as they develop. Thanks for reading.

Several rifles using Classic Reservoirs have risen to the upper lines of my ledger. As I work on them, I'll share them with you.

 direct e-mail link: Classic Reservoirs @ Barnes Pneumatic