by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
• Shoot it!
• Test it!
• Clean it — maybe
• Oil it — maybe
• Keep your hands off!
Today, I’m going to look at precharged pneumatics (PCP). Maybe you thought these came ready to go right from the factory, and in many ways they do; but even with this powerplant, there are always things you can do to make the guns shoot better.
The first thing is something most people are going to do anyway — I just want to make you aware of how it affects your gun. Shoot it! Don’t take it apart to see how it works and if you can “correct” all the flaws the “stupid” factory left in the gun when they made it. Don’t send it off to be tuned. Just shoot the thing, and it will get better.
Back when Falcon airguns were being made in the UK, they used to come from the box at one velocity — let’s say it was 890 f.p.s. with a .177-caliber H&N Baracuda Match. A thousand pellets later, the same rifle might be getting 960 f.p.s. from the same pellet. Falcons always increased in velocity as they broke in. That’s something my friend Mac taught me. He owned 6 Falcon air rifles, and each one of them got faster the more it was shot.
I started watching, and lo and behold my brand new Daystate Huntsman did the same thing. It started out at 875 f.p.s. with the same pellet and was up to 930 when I started competing in field target with the rifle, about 500 pellets later. Of course, to notice such things, you have to have a chronograph and use it.
The second thing you can do for your PCP follows from the first. Test your PCP to establish the optimum fill pressure. Don’t read the manual and then slavishly fill to exactly 3,000 psi on the dial of your fill gauge just because that’s what it says in the book. It’s a good bet that your gauge is off by some amount, anyway, so use that chronograph to find out what works best with your particular airgun and your particular gauge. Use the owner’s manual as your starting point.
My Daystate came with instructions to fill to 2,600 psi. But that didn’t agree with the fill gauge on my scuba tank — and THAT did not agree with the gauge on my hand pump that I ultimately used exclusively in competition. I discovered that if I filled my rifle to 2450 psi, as indicated by the gauge on my hand pump, the rifle gave me 24 shots that didn’t vary by more than 10 f.p.s. That information didn’t come from any manual — it came from testing the rifle over a chronograph with the pellet I intended using. Once I discovered that, I made an indelible mark on the cover of the gauge of my hand pump — a mark that is still there today, even though the rifle’s long gone.
Clean it — maybe
This trick I learned from the late Rodney Boyce, who sold me both my Daystates. He told me that PCPs shoot with dry bores, and they sometimes get lead in the rifling that affects accuracy. He said that, whenever accuracy falls off, you need to clean the bore. Then Ben Taylor — the Ben of Theoben — told me exactly how to clean an airgun barrel. Use a brass bore brush (steel barrels only) that’s loaded with JB Non-Embedding Bore Cleaning Compound and run it through the bore both ways 20 times. Clean out the residue, and the bore will be clean. I’ve been cleaning airgun barrels that way ever since, and it works.
And while I’m on the subject — don’t get hung up on the fact that Brownells calls their brush a bronze brush and I said to use brass. Brass or bronze — they all work the same. When the exact material really matters, such as when I say to use Silicone Chamber Oil, I’ll tell you that I don’t want you to use the silicone oil that comes in spray cans for oiling door hinges. And, I’ll tell you why.
Before I leave this subject, I have to say one more thing. LEARN ABOUT LEAD AND LEAD ALLOYS!!!! For over 50 years, I’ve had to know about the subtle differences between pure lead and certain lead alloys because I cast my own bullets. It really matters. If you use lead that’s been hardened with antimony, I guarantee that your bullets will leave lead deposits in the bore of your gun! I first discovered this in about 1968 while shooting a .45 Colt Single Action. But over the years, I have seen only a few gun writers who know that this happens or why.
Antimony is used to harden the lead alloy when you want to shoot a bullet very fast. Soft lead alloys will not withstand the rotational torque of the bullet when shot fast. In short, they’ll strip the rifling (they will not allow the rifling to grab and guide them) and will be inaccurate.
This leading happens more as the velocity increases, so until you top about 750 f.p.s. with pellets you won’t notice it. But when you shoot Crosman Premier pellets in an airgun at 900 f.p.s., they’ll lead the bore! It’s gradual at first, but it does accelerate as the lead builds up. Those using Premiers should clean their barrels when the accuracy drops off. But don’t be a slave to cleaning!
I know an airgunner who claims he cleans his barrel with JB Paste every 200 shots! Folks, that’s not cleanliness — that’s insanity! He’s being anal. This fellow will clean his barrel so often that a time will come when it will have to be cleaned all the time, because of the mechanical damage he has done from the rod impacting the rifling. Only clean your barrel when the accuracy falls off. And, if Premier pellets are the most accurate pellets in your airgun, by all means use them. I do!
Oil it — maybe
I do oil my PCP airguns. I use silicone chamber oil and put it in through the air intake port — the same way we put Crosman Pellgunoil into a CO2 gun. I know what this oil does for a PCP powerplant, and I do this as a matter of course. You don’t have to do it, and I am not advising you to. But if your PCP has a slow leak (loses pressure after a week), then some silicone chamber oil might fix it.
And, no — I didn’t say to use automatic transmission fluid or whale snot or Jake’s Sure-Fire Fix-it Oil. I said silicone chamber oil — period!
Keep your hands off!
The best advice I can give is going to roll right off the backs of those who need it the most. Leave your airgun alone! Just shoot it, and then shoot it some more. If there are adjustments (trigger, power, etc) avoid making them until you’ve shot your gun enough to know when an adjustment makes a real difference. I read about guys getting brand-new PCPs and tearing into them like they’ve been working at the factory for the past 10 years. They get knee-deep in the innards, and only then does it occur to them that they don’t know what they’re doing.
There’s a delicate balance between the striker weight, the power of the striker spring, the length of the striker travel, the diameter of the valve port, the shape of the valve head and seat, and the strength of the valve return spring. Is that complex enough for you? Your airgun has been designed to work best with the combination of these variables that’s in the gun when it leaves the factory. Changing any variable affects the others and may take the performance of your airgun outside the envelope in which it was designed to work.
When I worked at AirForce Airguns (2003-2005), I got to see the damage people will do to airguns. One case was particularly interesting, because the man who had brought us his nearly new and hopelessly broken Condor was posting on forums how to soup-up Condors at the same time he was asking us to fix the rifle he had destroyed. His “heavy” striker weight hammered apart the valve in his gun. It also ruined the screw hole in the frame that holds the threaded boss that the tank screws into. We fixed that as best we could, but he really ruined the rifle’s frame, which is the heart of the whole gun. Be wary of people who are self-proclaimed experts.