by Tom Gaylord, a.k.a. B.B. Pelletier
This topic was suggested by veteran blog reader Kevin. I liked it because it gives me a chance to say some things to the new airgunners; better yet, it’s a great way to start a discussion among all you readers.
I will touch on the things about chronographs, which are near and dear to me, but I think my role today is simply to get the ball rolling. We have enough readers with chronograph experience that I’m sure they’ll share a lot of their own viewpoints — some of which may never have occurred to me.
What is a chronograph?
The term chronograph means different things to different people. To an horologist, it might mean a particularly accurate instrument (watch or clock) to record the passage of time; but to a shooter, it means an instrument that’s used to measure the velocity of a projectile. It still records the passage of time, but also performs an additional calculation to convert the results into velocity. As incredible as it sounds, we’re able to measure the speed of a pellet or bullet moving hundreds, or even thousands of feet per second with an instrument we can buy for as little as a hundred dollars.
A modern chronograph is inexpensive and very accurate!
History
While ballistic chronographs have existed for more than a century, most of that time they were large, cumbersome, very expensive and difficult to use. It wasn’t until the 1960s that the first portable electronic chronographs became available to the common shooter — and even then they were still very costly and hard to use. You had to shoot through paper screens that had tiny wires running though them, and a sensor would detect when the resistance of the screen changed as some of the wires were broken by the bullet. These screens didn’t last very long in a shooting situation and had to be replaced when they could no longer detect the passage of the bullet. Time was wasted when things didn’t go as planned, and buying chronograph screens was an ongoing expense.
The early electronics were also quite troublesome from today’s perspective. They didn’t directly read out the velocity of the bullet. Instead, they registered the time that elapsed between screen one and screen two, detecting the passage of the bullet. And even that wasn’t direct! They did it by illuminating lights in various columns on a panel that the user had to interpret. The user took that number to a table and looked up the velocity. It wasn’t always given as one absolute speed, either. It was often given as a small range of velocities within which the bullet was traveling — like 2,140 to 2,148 feet per second. It was slow, crude and primitive, but it was the best we had at the time. This was also the time when we were using slide rules to solve complex math problems, and we accepted small margins of error when taking a reading.
These early electronic chronographs were also very imprecise by today’s standards. The precision of their internal “clock” was only about 1/10 to 1/40 that of today’s chronographs, so the number they gave…which was a best guess to begin with…was nowhere near as close as what we get from a modern instrument. Still, they gave us numbers, and we were fascinated by them.
When the first direct-reading chronograph (one that displayed the actual velocity of the projectile) came out, it boosted sales worldwide. Then, chronographs were easy enough for the average user. And when the first photo-sensitive sensors (skyscreens) came out, they did away with the expense and frustration of the old paper-and-wire screens. Both these things happened some time in the 1970s, if I remember correctly. That was when the private use of chronographs really took off.
A skyscreen senses the passage of a projectile by detecting the slight drop in light when the shadow of a pellet or bullet in flight passes over the sensor. Since the light source is often the sky, the name skyscreen became common. This is both good and bad. Good because of how easy they are to use, but bad since accuracy depends on how well the screens are lighted — but that’s a different topic. Today, I want to talk about what the availability of chronographs does…both for and to airgunners.
You use a chronograph to establish the velocity at which a pellet is traveling. All well and good. But the first time you actually do it, you’ll probably be awed by what’s happening. Then, one of two things can happen. You can either put aside your awe and get to work or become enraptured by the numbers the machine gives you and lose sight of everything else. I think that’s what Kevin wanted me to talk about when he suggested today’s topic
Problem No. 1: Speed rapture
The user becomes so engrossed in watching the chronograph readout that everything else stops. This once-sane fellow who used to love nothing more than making acorns dance with his pellet rifle now sits slack-jawed in front of his chronograph, watching the screen for the next number to appear. He no longer shoots at targets. He no longer cleans his gun. He just watches that screen. In extreme cases, he invents things to launch, just to see how fast they go. The chronograph has turned a shooter into a nerd. It’s the equivalent of an addition to a social network; and whether you like them or hate them, you’ve all seen what can happen when the network, itself, becomes the sole focus of a person’s attention.
Problem No. 2: Infinite dissatisfaction
The chronograph owner uses his machine to determine how much he likes a certain airgun. Because nothing is ever perfect, he’s never satisfied with anything. His chronograph has become like the magic mirror on the wall — but one with an extreme personality disorder. It spray-paints dissatisfaction on the overpass of his life.
This guy will buy an airgun, then shoot it over the chronograph until it fails to please him. You see, he’s learned that if you do something long enough, eventually you get the results that come from the bad side of the curve. When that happens, it sets off his spring-loaded trigger of dissatisfaction, as in, “I knew this rifle wasn’t as good as they said! And here’s the proof!” As Midas was unable to survive when everything he touched turned to gold, this fellow is in pretty much in the same boat; though, when he touches things, they turn into something far more objectionable.
Problem No. 3: The statistian
This shooter used to be the life of the party until he got his chronograph. He now carries a notebook full of columns of numbers that he will try to work into any conversation. You’ll ask him how things are going, and he’ll whip out a spiral-bound notebook with the numbers he’s collected over the past six months. Somewhere in all that data is the answer to how he’s doing — he just can’t quite put it into words. But he’s got the number to back it up! How’s he doing? Please turn to page 46.
Problem No. 4: Dazzled by the charts
This guy takes his chronograph numbers and creates charts with them. But he’s never taken a statistics course, so he isn’t really sure what the numbers are telling him. But he has found that he can tweak the presentation of the numbers on the charts to make them look any way he wants. For him, happiness lies in finding the best way to make his new airgun look good by adjusting the values on the scales of the charts. He’s really the same as guy No. 2, only his outlook is positive, where No. 2’s outlook is — well — it’s No. 2.
What good are chronographs?
It probably sounds like I’m against the use of chronographs, but that really isn’t the case. However, I do advise using them as tools — not as crutches. For example, do you first find the fastest pellet, then see how accurate it is? Of course not! First, you find the most accurate pellet, then see how fast it goes. If it doesn’t hit what you aim at, its velocity is secondary.
I see the same thing with those who reload centerfire firearm ammunition. They keep searching for the fastest load for a particular gun, with one eye always on the chronograph screen. They seem oblivious to what that cartridge is doing downrange — just as long as it’s the fastest in their gun. They paid for the speed their rifle can deliver, and by gosh, they’re going to get it! It’s akin to being the “fairest in the land,” don’t you think?
I turn this around by never consulting the chronograph until I have the most accurate round. Whether it’s a centerfire cartridge or a pellet, it’s all the same to me. I want to hit my intended target. Once that happens, I get interested in velocity, but only to know how fast the projectile is going — not to tweak it to go faster.
Okay, Edith pointed out that I test velocity before accuracy in my blog tests. That isn’t in contradiction of what I just said, because when I test an airgun here I am seeing what it can do in general terms. In other words, I am looking at power independently of accuracy. But when I test a gun for myself (and spend a LOT longer doing it), I’m interesting in the optimum performance it can give — not in the average performance out of the box.
Chronographs as diagnostic tools
A great use for a chronograph is to test the health of your airgun. If you know how fast it shoots with certain pellets, you can always test it again to see whether anything has changed. I’ve found things like broken mainsprings this way.
You can also use a chronograph to estimate performance of a certain pellet or gun. If, for example, there is an 80 foot-per-second variation in the velocity of a certain pellet in a certain gun, you can be pretty sure that gun will not shoot tight groups with that pellet at long range. They will be elongated on the vertical axis due to the large velocity difference.
Chronographs can also be used to calculate more complex things, such as the ballistic coefficient of a projectile by measuring its velocity at various distances from the muzzle. For this, you need more than one instrument since each projectile must have multiple readings along its flight path.
When I worked at AirForce Airguns, I used a chronograph to test the results of various repair jobs we did to customer guns. Of course, we never knew what the gun was doing before it encountered whatever problem it might have had, but we did know the parameters of a healthy gun. When the rifle was performing within those parameters, it was deemed to be fixed. You may have noticed that I often refer to the Crosman Premier pellet as a “standard candle.” That’s my slang way of saying that I use it in a diagnostic role since I know how fast a healthy AirForce rifle is supposed to shoot it.
There are also numerous other uses for chronographs, such as determining the energy a certain pellet generates, finding the optimum performance curve with a PCP gun and counting the number of useful shots you can get from a CO2 cartridge.
Before there were chronographs, shooters focused on hitting the target. They didn’t talk about velocity — they talked about power, as in, “This pellet rifle is powerful enough to shoot through a one-inch board.” After chronographs became widely available, some people lost sight of why they were shooting and became mesmerized by those alluring numbers.
You know that pellet guns are sold today on the basis of how fast they shoot. There are allusions to accuracy in the advertisements, but the velocity is always given. That’s what the modern chronograph has done to and for airgunning.
Chronographs are wonderful instruments, as long as they stay in their rightful place. Just don’t allow them to take over your shooting life and push the more important things aside.
“Of course, we never knew what the gun was doing before it encountered whatever problem it might have had, but we did know the parameters of a healthy gun. When the rifle was performing within those parameters, it was deemed to be fixed”
Strange thing, working rifles in need of repairs…
Interesting that this should come up today. I recently upgraded my Crosman PC77 to the steel breech. Yesterday I had it out and after dialing in the new sight I tested it on my Alpha Chrony just to make sure I hadn’t messed up the gun installing the “upgrade”. Best velocity average was 510 feet per second with with the RWS R-10 Match 7.0 Grain Wadcutter. No better or worse than before the modification. Crosman says 10 pump max and the reason the give is more pumps may result in air left in the gun. I decided to try going over that to see if my gun benefit from one or two pumps. I cocked and discharged after each shot and found no air was left in the gun. Each additional pump added velocity I stopped at 16 pumps when my velocity reached the advertised 600 feet per second. I have been shooting mostly inside and 4 pumps is enough to give me nice tight groups at 20′ . Is it safe to add these extra pumps? For the record it wasn’t that cold my Beeman P17 averaged 400 fps with the same RWS R-10 pellets yesterday.
David B,
The answer is not straightforward. The additional pressure in the gun won’t hurt anything, but the extra pumping does strain the pump linkage pivot points. Depending on the model of gun, these may have to be replaced with larger bearings to stand up to the final few pump strokes.
B.B.
I don’t think I’ll be buying a chronograph for a long time yet, At the moment I’m quite happy with measuring the time it takes a pellet to hit a stainless steel bin lid 30 yards away, i know when it doesn;t sound right even though it is a fraction of a second. I can tell that my Crosman 1077 fires a tad faster with lead free pellets than my .22 HW35 with AA diabolo, and my .177 AA Shamal is even faster, with the 2240 pistol with premiers being the slowest, as long as other rifles fall into the right ball park i can judge roughly how they are performing. Also using a test pellet to see how deep each rifle would penetrate a phone book has been good enough for a lot of people for years, and do i remember seeing a blog on splat charts( judging velocity by the deformation of lead round balls fired at a steel plate) a few years back?
So instead of spending money i haven’t got on a chronograph i can spend money i haven’t got on some decent scopes instead, and maybe an adjustable mount which i would find infinitely more useful. For me, I’m happy enough with a rough estimation of the velocity, and would only really need to know the precise velocity if any given rifle is exceeding 12 ft/lb in which case i would have to borrow the use of one.
TTFN
best wishes, Wing Commander Sir Nigel Tetlington-Smythe
You are absolutely right B.B., so many people are suffering from “Chrono Syndrome”. There is hope. Here at the RidgeRunner Chrono Syndrome Research Institute we are searching for a cure, but we need your help. Your donation will help us purchase a chronograph so we may do further research into this horrible disabling desease.
Howdy RR, at what donation price point does my donation get me a picture of the poor Chronyless child in far eastern Toadbutt, Festucia, who I’m helpin’?
Thanx ya’ll, have a great weekend, shoot/ride safe.
Beaz
Beazer,
What a scream! Thanks for bringing a big grin to my face this morning!
Edith
Howdy Ms. Edith, thanx for the response, I’m honored & thanx for lettin’ my Toadbutt reference slip through…wait for it…wait for it…here it comes…ya ready? The crack.
The current chronographs don’t seem to have the accuracy that I’d like. I’d really like to put a pair 10 yards apart and measure the BC more accurately.
I’m guessing that the problem is more the resolution of the sensor noting the passage of the pellet rather than the clock speed of the timer in the microprocessor.
Herb,
The spacing of the start/stop screens is another important thing. If they are off by 1/8-inch, the calculations go horribly wrong. Of course Shooting Chrony is usually safe from that, but noting is ever foolproof.
B.B.
BB – Good point. On a spread of 1 foot between sensors 1/8 inch is about 1%. When doing the calculations it also occurred to me that a pellet is about 1/4 inch. So the pellet passing over the sensor has a very finite interval.
I used to use Beeman Ballistic Putty, it came with a chart to measure the depth
of pellets in it.I found that it was pretty close to my chrono when comparing data
I now have a scale and I can separate the pellets and then I can get an even more
accurate reading.I think as long as you stay at the same distance at the chrono
for each shot the readings should be right on.
NNJMike,
Yes, as long as the viscosity of the putty remains constant. The viscosity changes as its temperature changes.
B.B.
Depends on what you want to use it for.
I use them for tuning PCPs. I also use them to get a better understanding of how my rifles work.
I don’t give a hoot about using them to come up with bragging rights on velocity, velocity spreads, FPE, or shot counts.
twotalon
When I bought my chronograph I learned my R1 was making only 11 ft lbs muzzle energy – time for a new mainspring!
What annoys me – I guess they are the #3 guys – are the people who post shot strings online and include the fractional part of the velocity – they will report 750.4 fps instead of 750. Since the maker only claims 1% accuracy, any number past the decimal is meaningless. Why bother?
“It spray-paints dissatisfaction on the overpass of his life.” – fantastic!
Paul in Liberty County
I was a teaching assistant when in grad school. On one of the lab worksheets a student came up with something like 123.6% Cu. I asked when it went over 100% why didn’t you realize that the answer must be wrong? “Well that is what the calculator said.” LOL
Herb
Exactly right, B.B.
I bought a brand new R7 and my F1 chrony revealed low velocity for that rifle and H&N sport wad cutters, around 520 fps. That rifle went straight in for warranty service along with a chrony printout of the low velocity performance. It came back with a new spring and the chrony verified that it was then shooting the same pellet in the proper velocity range. Problem solved, and the F1 gets all the credit.
To me they’re a necessary evil. Personally I hate lugging the thing around but it comes in handy when developing hunting loads.
Funny thing is I’ve never used it with my airguns!
dangerdongle,
Now I am just the opposite. I chrono lots of pellets and BBs, but rarely centerfire rounds. I guess it is because of the lugging thing you mentioned, plus the need to get the start screen so far from the muzzle.
B.B.
I bought a Beta Chrony three years ago. It was on sale so I went for it. I don’t use it much. It is a bit of a pain to set up and take down. Last summer, I had it at the range and shot my .25-06 hunting loads through it. I was shocked at the velocity. The 100 gr. bullets were going 3350 fps! My guess was about 3100. The rifle shoots 1 inch groups at 100 yds so the load is a keeper.
Be careful with the Alpha model. I saw a sabot from a muzzle loader take out the screen on one!
Mike
Mike,
The great danger with a chronograph is the person who sights through a scope and fails to account for the differential of the bore being two-plus inches below the optical axis. Both my chronographs have damaged screens from doing this.
B.B.
B.B.
I wonder how many have wasted their chrono because they thought they would get higher or more accurate readings by shooting as close to the sensors as possible.
twotalon
Yes. My windowsill can confirm this. I’m sure my chronograph eventually will, too. Not the optimal way to demonstrate the effects of scope-bore offset to your wife!
Blush,
Jan
I have used it with my air guns. My Diana 52 in .177 shoots 950 fps with JSB Diabolo Exact Heavy pellets. It might be a bit low but it is accurate.
Mike
It would be interesting if Pyramyd would create an accuracy metric with a mechanically reproducible method of shooting the gun that they published along with all the other specs. Of course they’d need to test all those guns – no small task. But if they started this, it might catch on with the manufacturers and eventually we might see accuracy numbers next to those fps numbers. That would be fantastic!
That might not turn out too well. The pellets that they use to get those velocity numbers would most probably not give very good accuracy. They would be cutting their own throats to do it.
Then there is the problem of each rifle/pistol shooting different group sizes with the same pellets.
Going to be a lot of returns.
twotalon
EdB,
While that sounds good in principal, it doesn’t work out. For starters, they only have a 10-meter range in their building. Ten meters is too close for such a number.
Ever notice that the manufacturers that include test targets generally charge 25 percent more for their guns than anyone selling an equivalent gun without a target? It is extremely expensive to test every gun, and the variables are such that testing a general model would never satisfy the customer who got one that didn’t live up to the stated expected accuracy.
Too many worms.
B.B.
Still, you must admit that today we have an accuracy metric that is published by Pyramyd on many guns. It is the “BBPAT” – the B.B. Pelletier Accuracy Test. I would never buy a gun without consulting it myself. I am only suggesting that it be standardized so we don’t need a hundred B.B. Pelletiers 🙂 – instead anyone can come up with more or less the same number (within a reasonable range). Admittedly, there are a lot of worms there, but the prospect of an “arms race” to reach accuracy goals that is like the “arms race” to make pellets go as fast as possible – this could have a huge positive effect on the industry.
and don’t forget (boy my college english teacher would have failed me immediately for using a conjunction to begin a sentence) the use of a chrony to show how a air gun is breaking in. Back on one blog I did for which rifle was the most accurate in my collection, I took out the first break barrel I had bought, an RWS 46, to test. When I was looking to buy it and doing research, an online spec from another blog touted this rifle being in the 8 to 10 ft.lb. range depending on the pellet. My own initial testing confirmed mine was on the high side of this range. Puting thousands of pellets down the barrel and then re-testing for that blog shocked me when my results showed the rifle now shooting at a solid 15 ft. lbs of energy with a RWS super H pellet! I was so surprised, I tested it twice. In fact, I think I’ll test it again tonight!
Fred DPRoNJ
I blame chronographs for (mostly USA) airgunners obession with velocity. Is it just a coincidence that about the time chronographs became affordable and widely available to shooters that the velocity race began and continues to this day? I think not.
This velocity race has lead to the majority of manufacturers designing springers and springer owners modding their airguns for speed alone. Accuracy, firing cycle, decent trigger, fit and finish don’t matter. Velocity is what sells airguns. I blame chronographs even though they’re inanimate objects 😉
I can recognize a new chronograph owner. His post on other airgun forums goes something like this:
“I’ve owned my gamo bone crusher for about a year and just shot it across a chronograph. This thing is only doing 950 fps and is supposed to be doing 1,250 fps. What could be wrong?”
Well Bobby, could be your elevation, could be that you’re not shooting 3 gr pellets, could be a broken spring, could be that your compression tube is out of round and not sealing ideally, could be your seals, etc., so why not tell us about your accuracy?
Yes, I own a chronograph. They’re helpful in quickly identifying the power curve in a pcp. I also use it to create a baseline for newly arrived guns so that over time if the accuracy falls off I can check fpe to determine if that could be a contributing factory.
I know airgunners that are obsessed with chronograph numbers to the point that they no longer shoot for fun but rather shoot for additional data accumulation. Different strokes for different folks I guess.
kevin
Kevin,
I think most people who are buying high-velocity guns don’t buy chronographs. Most of those guns are bought via the big box stores, and they’re not pushing chronographs…and I’m not sure they even sell chronys. They actually believe the velocities shown on the box, so why would they need a chrony?
Edith
Edith,
Because eventually most of these new airgunners find their way to an airgun forum and 80% of the chat on airgun forums is about chronograph numbers.
The newbie is brainwashed quickly into thinking a chronograph is a necessary tool.
kevin
kevin,
MOST of these new airgunners are buying one gun to eradicate pests or plink in the backyard. That’s it. They’re not going onto forums and seeking out chat. They have the fastest gun they can afford and are now moving on to other things.
Edith
Edith,
I agree with you.
I should have said “many” not most.
I should have also said their initial posts are usually seeking advice on how to shoot their master blaster with accuracy and many times they usually evolve into a chronograph owner.
kevin
Edith,
I think Kevin is speaking from the viewpoint of the new people on the chat forums. He is active on several forums and that’s where the land with their questions.
B.B.
Tom,
You’re correct.
This is also one of the main reasons I’m not very active on those other airgun forums anymore. The all too frequent posts about the constant fiddling with one’s airgun to squeeze out that last 23 fps of velocity have worn me out. May God bless them. It just isn’t me.
kevin
ps-this dialogue about chronographs has nothing to do with “need”. 😉
Kevin,
accumulating data and seeing what they can do to increase Chrony readings is probably a great source of fun to many of these fellows. It’s much like the re-loader that is constantly experimenting with power loads, primer seating, depth of bullet seating and crimping to determine what load will be the most accurate in their rifle. It seems like more of the fun is in experimentation and not how well they themselves can shoot.
Reminds me of that first air rifle when I bought it from a small shop in Media, PA. The owner spent considerable time showing me other rifles and laughingly telling me how folks in the UK would oil up their guns to obtain detonations to make their rifles shoot faster. Instead of calling the rifles Wembleys, many folks started calling them Wobblies as a result of the abuse they were taking 🙂
Fred DPRoNJ
Fred,
Re: “Great source of fun”
Many of these airgunners I’m referring to find their fun in tinkering with their guns. Different springs, different spacing, different lubes (have you read where dri slide is making a comeback LOL!), different pistons, different seals, etc. etc. etc.
Each time an internal change is made out comes the chronograph and then off to post this new, invaluable data on an airgun forum.
kevin
You forgot about those who need a faster shooting BB out of their CO2 action pistol… when they manage to actually make it faster without breaking anything (yet) they complain that the gun is now a gas hog or that the accuracy hasn’t improved. Ugh.
We get these all the time.
J-F
I like this article. I don’t own a chronograph since I don’t want to fall into the mentioned traps and don’t see a need for it. I pretty much take the gun with what is advertised on the box and call it gospel truth. In some cases like the crosman 17xx and 22xx series guns I make them into custom precision guns with plenty of spare power. How much? I don’t know, but it is better than stock. I did a beautiful one for a customer. It was all wood laminate, carbon fiber, stainless steel and highly polished aluminun that featured a few real gun parts as well. James Bond would have loved this gun. It was a work of art, mu opus. Only thing the customer was worried about was how fast does the pellet go. Eventually he destroyed this gun trying to bleed more speed out of it than I had already designed into it with sturdier hammer springs, larger beefier valves, extended bolt probe and more. Then he got mad at me when it broke. Some people just can’t be pleased.
John,
A man I used to work with was responsible for function-firing airsoft guns. He’d randomly select a few guns from each shipment and make sure they could eject a BB. He had no chronograph but “knew” what each gun’s velocity was. When I questioned him, he said that he can “hear” if it’s going a certain speed. Curiously enough, every single airsoft gun that was stocked shot the exact same velocity. When I asked him about it, he stated that he had very good ears and could distinguish a 20 fps difference. When I asked if he owned a chronograph, had ever used a chronograph or had ever compared his findings with a chronograph, he said he didn’t need to do that because he could tell just by listening to the noise of the gun when the BB left the muzzle.
Edith
That was one lucky guy! I wish I had ears like that!
I knew a guy who knew when things were leveled. He was very good and never checked his work either. 😉
J-F
J-F,
Some people really do have certain gifts, or just get really good with experience. When I first had my pool table installed, the installer was able to place the dot (forget what it’s called) dead center where it belonged with just a quick visual estimate. I took a tape measure and was surprised at the accuracy. Of course, he’s probably been doing this for decades, but it’s kind of cool to see a real expert do this thing.
Victor
That’s pretty good. I just take what the manufacturer says the gun will do and figure out a fairly accurate approximation of how much extra kick I gave the gun based on what I know a certain part is supposed to do for increase of pellet speed. So say a gun gets 500 fps stock, I add in a bigger beefier valve unit that is supposed to add 100 fps to the gun, then add a extended probe that tweaks it another 5 fps, then add a power adjuster that can tweak it another 25-50 fps, I know the gun should be firing full power around 655 fps which is what I tell my customer it SHOULD do. Notice i say should, not will. I figure I’m getting close to that number I’m doing ok. I use crosman pointed hunting pellets when I test things and make no secret about which pellet I use. The reason i use these isn’t because I get the best results with them or I have some fetish about them. It’s because those are the most readily available pellets I can get my hands on. Everything else lik JSB or Spitzdiddlys, or Critter hunter super weights or whatever I consider exotic due to the fact I can’t just go to the store and buy them.
I always wondered why mythbusters always used their highspeed cameras and their striped board to measure velocities. If the chronies available don’t suit their need they can surely know how to make one themselves and it would be easier than doing the math everytime doesn’t it? Maybe it would look less scientific?
Chronies can also be used with the kids. We have nerf guns and I recently bought nerf blowguns, I want to chrony our results to see who can shoot them the fastest and what technic works best (short stronger blow or longer, more regular blow). With adequate protection or a clear piece of plastic it could chrony how fast a HotWheels is going on a track and then multipling by 64 (most HotWheels are 1/64) would give the speed it would be going at if it was a real full scale car!
I love measuring tools. Did you know that beard hair are much thicker than hair (for those of you that have some left 😛 ) ? I go around the house with the digital caliper and the kids and we measure stuff up and we do the same with the digital thermometer gun but apparently the only difference between science and goofing around is writing it down, we’re mostly goofing around.
J-F
A lot of the Mythbusters stuff has sizes or trajectories that common chronographs wouldn’t work well. Or, wouldn’t be comprehensible to the viewing couch potato vs the visual effect of super slow-motion.
No Edmund Optical comparators?
http://www.edmundoptics.com/microscopy/magnifiers/comparators/edmund-6x-junior-comparator/1727
I own a chronograph because in Canada, 500fps is the fastest you can shoot without a PAL permit. I’ve mentioned the futility of this law many times here, as have J-F, and others. The chrony tells me if I can add or have to subtract spring coils in order to stay legal. I have to get to the Ophthalmologist in an hour to receive an injection in my right eye. I have the dread macular degeneration, and it has forced me to learn to shoot left handed. So, if these injections bring my right eye up to snuff, I will be an ambidextrous shooter. Sometimes you can get a good deal on left handed guns that haven’t moved in the dealers.
Caio Titus
I find it interesting that no one seems to mention the temperature or elevation they do their testing, when using spring or pump guns. The absolute pressure of the ambient air will dictate how much air can be compressed in the piston or holding valve, thus the power that can be developed. I live above 3600 ft elevation. Ambient air pressure here is about 10% lower than sea level. For a given number of pumps, my guns will not have as much compressed air stored in them as one at sea level, and someone in Denver or Santa Fe will have even less, so chrony values at a higher elevation will necessarily be lower with all other things being equal. A CO2 or PCP will be less affected by ambient air pressure. I do believe there should be an industry standard set of conditions and pellet used to determine the ‘standard’ velocity, as opposed to the ‘up to’ velocity marketing departments seem to like. Everyone would understand the velocity spec to be a reference to compare one gun to another and nothing more, and the velocity determined by averaging many shots. Pyramyd AIR could be a leader in setting such a standard. A ‘velocity standard’ pellet should have the following characteristics:
1. Be readily available anywhere.
2. Be affordable for anyone.
3. Be middle of the road in weight, not super light, nor super heavy magnums.
4. Be high enough quality that there is reasonable uniformity.
Rob Norris,
Actually Kevin did mention elevation while making a point similar to yours.
Victor
Definitely a good point, Rob. I live at 5500 ft and most of my airguns don’t perform to spec. I can put 12 pumps in a stock Benji without retaining any air in the valve after firing, my springers are all way under powered from what they would be at sea level but fire just as harsh. The single strokes like a P17 are pretty wimpy and my one and only pcp takes a lot more pumps to get out up to pressure. The only things that seem to be unaffected are the co2 guns.
/Dave
There is another factor in play here. As elevation increases, and air becomes less dense, resulting in less
air in the gun, it also presents less resistance to the pellet in flight. Will that balance the decrease of air in the gun at altitude? I don’t know.
I live at 3200 ft. This is the lowest elevation I have ever shot my airguns (except when I was a kid). The highest elevation I have shot them at was 9500 ft. I did a lot of airgun shooting in New Mexico at 4300 ft.
Shooting springers and multi-pump pneumatics, I really didn’t notice a difference at different elevations.
Les
Another thing just now occurred to me. The speed of sound changes with altitude. I think it increases with an increase in altitude.
This should have an effect on airguns shooting in the trans-sonic range. Would this have an effect on pellet choices, say between a gun shooting at sea level verses 5,000 or 10,000 feet? Has anyone done any experiments with this?
This is another result of change in air density.
Les
Nope, not density. The speed of sound in a given gas depends only on temperature.
(PLEASE HELP!) I have a crosman TR77. I recently bought crosman rmcoil for the compression chamber. I put 1 drop of it in the compression chamber and left it like that over night. I got up the next morning to hunt and when I took a shot at A squirrel… The gun made a very loud bang and tons of smoke came out of the end of the barrel. I live in suburban area and cannot afford to shoot it again(due to the loudness). Was that just an after effect? Or is part of my gun damaged?
Ryan,
You only have to ask a question one time he3re. I answered it where you asked it the first time.
B.B.
Ryan,
Keep shooting the lightest weight pellets you can find into a safe pellet trap indoors. At around ten shots you’ll hear it quieting down, and by 20 or so it will be normal. Then, only oil it when it starts honking like a goose when you shoot it. That’s when you know it’s getting dry and needs another drop or two.
If after you burn off the excess oil it’s still too loud for your neighbors, you can get a moderator from one of the suppliers on the yellow classifieds.
/Dave
Sorry, just noticed that Vince already answered you below…
You detonated the oil. Generally speaking you don’t put anything in the compression chamber because of this. Over the long term it CAN damage your gun, but it takes a great many shots to do this.
In my experience it’s far better to add lubricant in the cocking slot behind the piston, where it’ll work its way around the compression chamber walls without getting dumped all at once into the chamber.
Your best bet is to shoot it indoors somewhere (basement or garage) until it stops detonating. It shouldn’t take that long.
Ok thanx. and Then why did the manual tell me to do that?
I suspect the manual may have been written by someone who’s thinking of a BB gun or multi-pump pneumatic.
Here is what Ryan Cole is talking about. I copied this out of the TR77 owners manual:
Quote:
7. Maintaining Your Airgun
•
Periodically tighten all stock fasteners
•
Check and tighten scope mounts if applicable
•
To ensure that your air rifle maintains uniform power, it is important that
you apply a drop of Crosman RMCOIL every few hundred shots into the
compression chamber. (Fig. 8) The external metal parts should be cleaned
with a cloth that has RMCOIL on it.
CAUTION:
Use Crosman RMCOIL only and do not over-oil. To do so can
cause possible damage to the gun and injury to the shooter and bystanders.
ENDQUOTE
The Figure 8 mentioned shows the gun cocked open with an arrow pointing into where the head of the piston is so it is suggesting that you put the oil directly onto the piston head.
Ryan’s point is well taken and I think he has a valid question, but there is the “do not over-oil” rule, which is subjective since that is such a misunderstood rule.
Ryan says he put only one drop of oil in and that doesn’t sound like over oiling to me.
Do we have a case of improper oiling instructions here?
-Chuckj
Here is the link to the TR77 owners manual. You can find the Fig 8 pic to see the recommended oiling spot. Funny how the blog editor changed the 8 followed by the closing paren as an emoticon.
https://www.crosman.com/pdf/manuals/30001-515.pdf
-Chuckj
chuckj,
We have a caae of the manual writer not knowing the correct interval for oiling a powerful spring gun. They shouldn’t put this in the manual, because even one drop is too much oil. That gun needs to be THOROUGHLY broken in (5,000 shots at least) before oil is applied, and only then under certain conditions, such as a squeaking piston seal.
B.B.
To actually say something on topic for once….. I use my chrony pretty much for my airguns health or if I got a new gun and want to see what it does. I use it with my firearms rarely if I’m curious about a load I’ve developed for one of them.
/Dave
HI all,
As a match director, we use a crony to make sure the competitors are not shooting too powerful air guns for the class they are entered in. All competitors have to pass the “crony test” in order to compete in the match. We also test the competitors part way through the match to catch those that might increase their power after the “pre-match testing”.
I’ve made a box with legs for my crony with a front ledge/channel for the barrel to be placed in. This insures that the gun is held in the right position and level.. and my corny won’t get shot:-) I also added a full one piece sky screen at the top of the box, which is a 1/16″ thick sheet of white plastic, since those bracketed factory screens are flimsy and such a pain in the A ….. I then used the same light fixtures just laying on top of the plastic roof. It’s much quicker to use and gives more accurate results over and over again.
I do find it a little interesting, that the industry fashioned consumer, is so concerned with fast velocities instead of accuracy… but if it works with cars, then why won’t the same marketing plan work for pellet rifles and pistols?
Other than testing competitors, I use the corny to find the best shot curve after a new tune on a PCP…. and others in the club use it to test rigs after repairs like new springs or breech seals. It is nice to see a very tight spread on a shot curve and I can see how some folks might want to share that good news with the forums.. we all have our pride, don’t we?
And when accuracy really is important to you… don’t forget to look up their skirts… the pellets that is:-) Weighing is not enough.. dented skirts and debris in the skirt, WILL cause minor inaccuracy like a 9 instead of a 10 at 25 meters.
Happy safe shooting,
Wacky Wayne,
Match Director,
Ashland Air Rifle Range
Wacky Wayne,
Since you check each competitors rifle velocity, do you also weight their pellets, because that’s a significant part of the how much power their putting out?
Victor
Hi Victor,
Yes, we weight out 5 pellets for the competitors pouch and then have them shoot them across the corny… and we have a chart for the fastest each weight pellet can go in a given class.
Wacky Wayne,
This is all very interesting to me, since I’ve competed in highly regulated competition. Is this done on the same day of the match, or some time before? Are tins, or containers sealed, only to be opened when the match starts? Just curious as to how you may try to discourage, or limit, cheating.
Thanks,
Victor
Hi Victor,
We use the competitors pellets, weigh them right before the test, find the fastest that pellet is allowed to go on the chart, and let the competitor shoot them across the crony before the match, (usually at the sight in area well before the match)… then we have a special lane on the course, during the match, that the competitors don’t know about… so if they have increased the power on their gun after the first test, they will come across this test lane on the course. The other competitors in their squad, who also score each other, should notice if someone is trying to reduce their guns power as they approach the testing lane. When they get to that lane, the other competitors in that squad will test each others gun and sign off on the testing on the back of their score cards.
It’s not perfect, but enough of a deter-ant to discourage most cheating. When a shooter is over 20fpe, (the highest allowed in “Open Class”) we will also notice damage (deep dents) to the targets on the closer shots… that’s a signal to look more closely at the competitors gun power levels.
Most competitors would never even consider cheating… I can’t remember ever hearing of a cheater getting caught… Winning is not the most important thing to most of us. It’s more about getting together to socialize and testing our own personal skills against the last match we shot.
Note that this testing is only done on the championship matches, local club match directors very rarely test for the monthly local matches… but if they see damage to the clubs targets, they can get a little cantankerous. Local clubs are usually very generous about letting new shooters “use what they’ve got” to try out the sport, so in that case, over fpe is overlooked unless they are way over and really damaging targets, then the club will lend a quality FT rig to the new shooter, so they can really get a feel for the game.
Find a club in your local area, (here is a link to a list of clubs in the US http://www.network54.com/Forum/451309/), and try it out! I bet you’ll have more fun than you could imagine.
Wacky Wayne,
Match Director,
Ashland Air Rifle Range,
Ashland, Oregon
Wayne,
I tried your link but got a page not found error. I think the error might be in the number at the end because I did get to Network 54 site.
-Chuckj
Given the subject of the previous blog entry I hesitate to point out that the term is statistician
And a general comment to the world, inspired by the nice close-up of the “Alpha” model you show.
Note how the display/control is mounted on the front face. A low shot could ruin your whole day (though the “Shooting Chrony” folks seem to have a fairly decent repair/upgrade pricing scheme.
Using the “Shooting Chrony” line, the Alpha, Beta, and Gamma models also have “Master” variations, which use a phone cable to connect the sensor boxes to a portable control head. The extra cost for the Master models could be worth it (especially when one has to sight on a target to ensure not missing a backstop, and has something like an AirForce Condor with 4-16x scope… I put a nasty dent on the front of my Beta Master model due to the height difference between the scope and bore, while using indoor LED “sky screens”).
Other makers of chronographs also have remote control heads, but tend to be much more expensive than the “Shooting Chrony” line (granted, they run faster clocks allowing more precise timing, may use three screens to reduce noise effects, etc.)
I don’t recall what the Gamma model adds… The Alpha, as I recall, is single string of 10 shots. The Beta can record 6 strings of 10 shots each (they hold the memory so you can read the data out later — probably useful if one is just testing a few sets of handloads; that’s 60 rounds total in 6 “loadings”).
One can also obtain a printer for these, and can print out the results as-shot or after-shot (after shot will also list max/min/mean/st.dev.)
\
You can always set something if front of the unit to protect it.
Mike
Perfect example of sticking ones neck out too far:
Shooting the chrony itself? What the heck is wrong with you guys?! Basic shooting rule #1 – always know where the muzzle of your gun is pointing.
Insert total lack of sympathy here: o
-Chuckj
It can still happen even if you know right where the muzzle is. As I said earlier, I saw one take a direct hit from a sabot from a modern muzzle loader. The bullet went right where it was aimed.
Mike
Mike,
You said: “As I said earlier, I saw one take a direct hit from a sabot from a modern muzzle loader. The bullet went right where it was aimed.”
I must be misreading your comment. It looks like you said “they” aimed right for the chrony and hit it. Normally that’s called good shooting. 🙂
-Chuckj
Yes, the way we write things doesn’t always come out the way we want. The sabot separated from the bullet and hit the crony. The bullet went over the sensors OK but the sabot hit right in the middle of the display. Not a good day!
Mike
Ouch!
BB: You are the poet laureate of air guns. Thanks for such excellent interpretations
After getting his chronograph, the shooter was never heard from again. So, are these out of stock along with everything else?… Actually, I was able to order some A Zoom snap caps for my Mauser which is what I expect it to be shooting for awhile.
Victor, as a matter of fact, I made my breakthrough with the hard trigger. It came down to a single bull where I had to put down the rifle three times. But I finally managed to squeeze through, and I did some of my best shooting with the B30. So, I’m back. One thing that gets lost in the discussion about guns is how amazingly fun they are. There is high drama every day, and I can hardly imagine life without them. I can’t think of a substitute.
Mike and Wulfraed, thanks for making me aware of the Marines’ new rifle. I had thought that they were going to drop the IAR concept and here they have a number of the rifles in action. With the piston version going head to head with DGI in the field, I guess we’ll see comparisons pretty quickly and maybe we will resolve this question once and for all. I actually have not heard that many great things about the HK 416. It’s an example of German overengineering although it works. I would prefer the old AR18 that Eugene Stoner himself designed. Apparently, the IRA were very pleased with the weapon, and it is the basis of the German G36 rifle that is very successful. The answer is right under our noses.
The IAR sounds a lot like the old BAR concept updated. I also heard that the Marines are dropping the M4 in favor of the M16A4 design as part of their ethos of being long-range riflemen. Anyway, it’s nice to see that the Marines are no longer getting the dregs of equipment as they have for much of their history.
Matt61
I can sell you some 8mm Mauser ammo if you want to try out your rifle.
Mike
Matt61,
Now you’re describing how I feel about shooting. When communicating with the City that wanted to end their marksmanship program I explained that my experience was very likely entirely different than what they, or most others could imagine. I explained that in all the years that I competed I never saw my guns as “weapons”. Instead, I saw them similar to how one might feel about an instrument. I explained that my guns were like an extension of my body and mind, and that they allowed me to measure performance in terms of both body and mind. That’s how deep shot execution was to me. I honestly never thought in terms of winning, losing, or getting awards. The only thing that mattered to me was one shot, and that was the shot that I was in the middle of executing. So for me, each shot was a special experience.
I also understood that whatever limitations I was experiencing were only temporary. Higher levels were achievable, I just needed to solve whatever problems were limiting me. With this belief system, shooting helped me to be come optimist. I don’t want walk away from a disappointing experience with the idea that it was some kind of end, or proof of anything. Instead, I always walk away know that I’ve just got some problems to solve. So IF I ever feel frustration, it’s very short-lived.
So shooting is both satisfying, and rewarding. That also makes it fun, as you’ve discovered.
Victor
I have searched the material here and I don`t see any reference to Chairgun Software from Hawke scopes. . Using Chairgun with the speed of the pellet allows the shooter to get the proper mildots required to shoot at various distances.
This I could not live without.. or if I did it manually it would take a lot of research..
Thanks.