Why own a chronograph?
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- No preaching
- Evaluate an old airgun
- Test pellets
- Evaluate a tuneup
- For detailed tuning and product development
- What it isn’t
Today is my cataract surgery. I don’t know how well I will be able to function online for the next several days, so will you veteran readers please help the new guys? I know you always do, but I’m just telling you what’s happening.
If you have read this blog for very long you can answer the title question for yourself, because I write about chronographs all the time. I use them for big things like testing the health of a new acquisition (the Sharp Ace Target and the Sheridan Supergrade), and things more subtle (testing the Air Arms Galahad).
I used to preach about when to use a chrono and when not to, but I’m not going to do that today. Use it whenever you like and for whatever reason suits you.
I was disturbed by the airgunners who buy an airgun and then chrono it to find out whether it is a “good” gun or not. Yes, that does happen, and a lot more frequently than you might imagine. So what? If that pleases them it certainly doesn’t hurt me. No preaching today!
But that’s just one reason to own a chronograph. What are the others?
Evaluate an old airgun
When you acquire an old airgun, you can tell the state of its health with a chronograph. You have read where I did this with several old airguns, but how about one as an example? Do you remember back in 2016 I tested my Sheridan Blue Streak for you? I started the test as a memorial to my late wife, Edith, but when I got to test the velocity I saw how tired that old rifle was. With Crosman .20 caliber Premier pellets the best I could get was 486 f.p.s. from 7 pumps. The gun was 38 years old at the time and it was clear the seals had hardened with age. If anyone asks you how long a multi-pump pneumatic will last between rebuilds, the answer is 38 years.
I had the rifle rebuilt by Jeff Cloud, who I work with for the Texas Airgun Show. Jeff and I were talking as the 2016 show was getting close and I learned that he had taken up rebuilding older Blue Streaks, so I gave him my rifle to overhaul. When I got it back it would shoot the same Premier pellets at 582 f.p.s. on 8 pumps and 609 f.p.s. on 9 pumps. That’s a gain of more than 100 f.p.s. from the overhaul. And it took a chronograph to show it. I certainly would never have known all of that without one.
I would not rely on just a chronograph to test pellets, but chrono results can be useful. Think back to the tests you’re read where I got a 300 f.p.s. velocity spread with a particular pellet. That would be a pretty good indicator of a pellet that isn’t going to do well.
Evaluate a tuneup
You want to know what a tuneup has done for your airgun. I do this a lot. Sometimes it is an entire tuneup, but other times it is something small, like the replacement of a breech seal in a breakbarrel. I have probably done over a hundred such reports for this blog over the past 12 years, but the one I liked best was the 10-parter I did for the RWS 45, whose piston I buttoned. If you recall, that rifle was tuned for Johnny Hill, the owner of Tin Starr Bullets. He liked the rifle a lot, but I told him I thought I could make it shoot a lot quieter, and that entire series documented me doing that.
The part I liked best about that series was the fact that I wasn’t satisfied with the results of the tune and I disassembled the rifle to lube it one more time afterward. It was still more powerful than it had been when I got it, plus it shot as smooth as any air rifle I’ve tested. I was proud of my work, which is a job well done. And a chronograph told me what my work had accomplished.
A second favorite of mine was that tired old BSA Super Meteor Mark IV I had to completely rebuild. That rifle put me through the wringer, but my chronograph kept track of where things were at all times.
The point is, without a chronograph I would never have known where I was starting from or where I arrived when it was over. But there is one more thing to say about this. A chronograph is just one tool you use to evaluate an airgun. If the gun isn’t shooting smooth or accurately when you are finished I don’t care what the numbers say; you are not finished!
For detailed tuning and product development
This one is for tinkerers and for the airgun companies. A chronograph can tell you when things work and, more importantly, when they don’t. I have a couple stories here. The first comes from a conversation I had with Ben Taylor — the Ben in Theoben — at the SHOT Show many years ago. We were discussing his Theoben Eliminator/Beeman Crow Magnum. He told me one of the worst decisions he ever made was to put a valve on his guns so users could adjust the air pressure in the gas spring. He said so many guys just pumped it up until they could barely cock the rifle, which is somewhere around 75-100 lbs. of effort. They thought they were getting maximum power then, but Taylor told me what they were doing was playing with a slide hammer and beating their airgun apart. After that Davis Schwesinger of Air Rifle Specialists sent me a piston seal that he removed from an Eliminator someone had destroyed that way.
This piston seal was vaporized by over-pressurizing the gas spring of a Theoben rifle. There is a deep hole in the seal where it was vaporized over time.
I also have a happy story for this one. In 2005 I had approached the Crosman Corporation about building a unique new PCP that only had to be filled to 2000 psi. When I met with them in early 2006 their head engineer, Ed Schultz, told me he had initially thought I was crazy when I made my proposal. So he prototyped a Crosman 2260 CO2 rifle (they are called Sheridans now) to see what would happen. To his surprise the rifle was shooting nearly 900 f.p.s, without any modifications to the CO2 valve. When he adjusted the valve he got it up to 1,000 f.p.s. with Crosman Premier lite pellets. He did this in three days, once my airplane reservations were made for the meeting.
If you have ever watched an infant soil his diapers to his great relief you have an image of the faces I confronted in East Bloomfield on that historic day when the Benjamin Discovery was born! They were beside themselves with joy and forced themselves not to smile too much. Ed (I know he reads this blog every day), I will never forget your expression! Obviously a chronograph was involved.
What it isn’t
A chronograph isn’t a substitute for joy. Joy comes from shooting an airgun that’s right in all ways. What the chronograph tells you is where that is, in terms of velocity. If you are hitting the target every time, stop worrying about the numbers. Annie Oakley never knew how fast her bullets were going, but that didn’t seem to matter.