by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- So what?
- The most important thing
- What gives accuracy — the barrel
- What gives accuracy — the trigger
- What gives accuracy — the breech lock
- My idea
- Between the lines
This is the start of a series that I think will be quite different. The inspiration comes from the SpaceX company that has now successfully put two astronauts on the International Space Station. SpaceX has significantly reduced the cost to build rockets and launch payloads, making space exploration more affordable. Elon Musk determined that he could buy the materials to build a rocket for just three percent of what the Russians wanted for theirs. That was what put him in business.
What does any of that have to do with airguns? Everything, I think. Because it illustrates just how much can be accomplished when there is a plan and when the schedule is not artificial but is based on realistic forecasts. This report is not meant to criticize any company or person, but it will also not permit the hardening of attitudes that stifles progress.
We are going to design an ideal airgun. In fact we are going to design a couple of them, and I am starting with the spring-piston powerplant. This will be an air rifle
If we are successful, we will design an air rifle that can be manufactured at low cost and yet have all the things shooters desire. I will start the conversation, but you readers are as much a part of this as I am. So — speak up!
The most important thing
I think the most important thing about an airgun is that it hits what it’s shot at. Power alone is not important because power without accuracy is meaningless. Beauty isn’t of chief importance because, while it might satisfy the taste, if it can’t hit the target it won’t get shot. Ergonomics aren’t that important because it can fit like a glove — if it doesn’t also hit the target it’s not going to be picked up. Price is not the primary importance because if it can’t be relied upon to hit the target, who cares how cheap it is?
Nobody made me full ruler and controller of anything, so if you disagree with me on this point, make your case. I’m not saying that power, beauty ergonomics and price don’t matter; I’m saying they only matter once there is an accurate airgun to apply them to.
What gives accuracy — the barrel
Accuracy is not just the barrel, but it certainly begins there. Crosman has learned that if they first ream the inside of the barrel tube before they rifle it, they get the best results. Sig has learned that the barrel doesn’t have to be choked — as long as the bore size is relatively uniform from breech to muzzle. Add that to what Crosman has learned and we know what must be done to rifle an accurate barrel. AirForce has learned that by cutting a progressive leade into the rifling at the breech, pellets will load straighter and deform less when shot. Add that to what Crosman and Sig have learned and we start to see the beginnings of good barrels.
FX has learned that it is possible to swage in the “rifling” from the outside of the barrel and lower the cost to make a barrel. But, they also know that a barrel rifled this way will be very picky about what pellets it likes. The barrel will be very accurate with a certain pellet within a certain range of initial velocities, but that range must be maintained. Oops! Perhaps we have gone too far.
I could go on and talk about lapping the barrel after rifling. Bartlein laps before rifling and again, after rifling. Their barrels are considered some of the finest in the world. But for our project, I think lapping after rifling is one step too far. It takes a $100 barrel and makes it a $250 barrel rather quickly. If the reaming process is run slow enough and the tools are kept sharp enough to prevent chattering, I think we have gone as far as we need to.
What gives accuracy — the trigger
An accurate air rifle needs a good consistent trigger to realize its maximum potential. But it doesn’t have to be a 50-gram trigger from a 10-meter rifle. I have told you of the benefits of the ball bearing trigger that certain vintage Dianas have. They were great for their day, but that day has passed and those triggers contain far too many parts to be economically acceptable. We also know that Rekord triggers have been superb for nearly 70 years, and the Air Arms version is the highest evolution of that design in production. Ivan Hancock used to make and sell a brass version of the same trigger that was called the Mach II, and that handmade version was perhaps as good as the design ever got.
But we don’t need a trigger that good in our ideal air rifle. Let’s turn our attention to Sig, instead, and look at their Matchlite trigger that’s in the ASP20 breakbarrel rifle.
Sig Matchlite trigger. Graphic provided by Sig.
Sig produces an American-designed airgun trigger that’s ideal for our project rifle. Ideal, only we can’t use it unless Sig also builds the rifle. What it demonstrates is that the Rekord is not the only good airgun trigger design. The Matchlite cannot be adjusted as light as the Rekord, but within the box of its performance it’s good enough for the rifle we are building.
The adjustments on Sig’s Matchlite trigger work inside the bounds of safety. You get a light trigger that the lawyers are okay with.
What we need is a trigger with the adjustability of the Matchlite but with simplified design. It needs to have fewer parts and should retain some adjustability. And it should have a positive trigger stop.
Yes, there should be a safety. It should be ambidextrous and manual.
Design the breech so one hand has to pull down on the muzzle of the barrel to fully access the breech for loading. That’s your anti-beartrap. You just made the shooter part of the safety equation.
What gives accuracy — the breech lock
Sig also showed us that a breech lock can be built that locks up a breakbarrel like a bank vault without an overly aggressive detent. Their Keystone breech is light-years better than any other one on the market. But is that the only way to do it? I think not. I think with some thought a different type of lockup can be created that doesn’t infringe on the Sig patent — unless Sig decides to built the rifle I’m talking about!
Spring-gun manufacturers other than Sig haven’t been investing any thought in how to lock a breakbarrel breech or how best to reduce friction in the pivot joint without allowing the base block to wobble when the barrel is closed. Through corporate hardening of the attitudes they have put progressively heavier detent springs and more aggressive chisel detents into the hinge joints. I can think of a system right now that would lock a breech solidly and be nothing like the Sig Keystone. And I am not an engineer!
The powerplant is where this project really takes off. In the recent report on the Beeman R10 you learned that the piston stroke is where power lives — not the diameter of the piston. Now, stay with me on this.
Why do people love the FWB 124? After the accuracy, the one big reason for liking the 124 is how easily it cocks, relative to the power. So, let’s do this — let’s reduce the piston diameter to around 20mm, and let’s increase the stroke to around 90mm. Let’s reduce the power of the mainspring to a third of what it is now to create a breakbarrel that cocks with 15 lbs. of effort, yet puts out 12-13 foot-pounds in .177. Can it be done? I’m not sure, but it would be something to strive for.
The Vortek PG3 tuning kit suggests what kind of powerplant parts are needed to do what I’m suggesting. Knowing that up front means designing a powerplant from the beginning that meets the specification for light cocking, reasonable power and vibrationless operation. Button the piston during the design stage and make the buttons easily replaceable (they literally fall out when the piston is out of the spring tube!). Or, take a page from the TX200 book and put a rotating nylon ring front and rear on the piston with no possible spring tube contact of the piston body in-between.
What if the piston wasn’t made entirely of steel? What if the body was nylon with a steel head? The loss of weight would combine with the lighter mainspring and tighter powerplant tolerances to eliminate vibration.
What a powerplant like this gives us is a rifle that doesn’t weigh a lot. That’s why I say it should be a breakbarrel — to keep the weight off. I’d like the rifle to weigh no more than 6 lbs. And lighter is better. That means a synthetic stock. I want a stock with a 14-inch pull, a sculpted pistol grip with a palm swell that fits both right and left-handed shooters equally well. It should have a very slim forearm that’s not too deep. We save weight plus get a rifle that feels right instead of a fencepost! Fill the butt of that stock with sound and vibration-damping compound, or cross-braces that create the feeling of a solid butt without the weight.
I have spent a lot of time discussing good open sights with you, and several readers have taken up the crusade. Ditch the fiberoptics, or at least make them either optional or an included part that doesn’t have to be installed. The basic front sight should be a square post that is sized to match a square notch in the rear. But — make the sights removable so options can be installed by the owner.
Sure — give them a Picatinny scope base on the spring tube — BUT — make it a screw-on option!
The rear sight should be easily and positively adjustable for both windage and elevation. There are plenty of good rear sights on the market today, so this should present no challenge.
There — that’s my idea for a new spring-piston air rifle that I believe would be very popular. It’s nothing like what you are ever likely to see, but if each feature/component were done right, and that means as close to what I said as possible, I think the world would have a new icon to celebrate.
But who says I know what everyone likes? Well, I sort of got it right with the Discovery, didn’t I? I missed on the Rogue, but what Crosman brought out under that name bore no resemblance to what I briefed them on. I was in the hospital while that one was being put together. And the Bronco was reasonably successful. At least people liked it once they shot it.
Between the lines
If you know the airgun industry you can read between the lines of today’s report. Some companies are in better position to execute such a new spring gun than others. But the sad thing is when the ammo trucks arrive at the battle a half hour too late for resupply. Let those who know understand!
Now, you readers take it from there. Or tell me why I’m wrong and what needs to be done, instead.