Yep, BTDT! I was testing some 44 Magnum handloads and one of the metal screen holders just disappeared. I look for mebbe a half hour for that little guy, gone! Next day went to the hardware store and picked up some appropriate diameter dowels. Now if I hit one, it'll just break and I keep a spare or two handy...Originally Posted by MrWolf
My Anchor is holding fast!
I guess I'm just lucky. I haven't done that yet.I still have my original Chrony. I have a couple of others because the first one was difficult to make work but none of them have been shot.Don't forget to buy another one. That way you can have one to use when you shoot and kill the first one (you will!!!, ask me how I know!!)
And remember that a scoped rifle has the bore well below the line of sight. (another believe me, I know)
Chronographs are the cat's meow for testing firearms for consistent ignition, bullet design & alloy.
Any firearm I want to use for competition or sd gets tested for consistent ignition. Get a firearm right & tight and the es's/sd's will drop which ='s consistency/accuracy. I've seen firearms cut their groups by as much as 40% when tested over a chronograph. Along with cutting huge swings in velocity out of short bbl'd firearms.
Bullet design plays a huge role in performance/velocity. A bullets performance doesn't matter as much in high pressure/high velocity cartridges. Start getting into short bbl'd firearms or looking for a hot hv hunting load that's accurate, a chronograph and a bunch of different bullets come in handy. Awhile back I did some testing with some short bbl'd 38spl's & 357's with these bullets along with a hbwc turned backwards and a hbswc.
[IMG][/IMG]
The 2 1/2" bbl'd 357 didn't care what bullet I used, was looking for a 1200fps 357 load and all of them delivered. So I chose a sd bullet based on the hp's performance. The 2" bbl'd 38spl on the other hand had as much as 50fps difference in velocities between bullets. In a 4" or longer bbl'd 38spl, it wouldn't matter. In 1 7/8" or 2" bbl'd 38spl's a difference of 50fps by simply using a different bullet is huge.
I've always liked a chronograph for testing alloys. Find an accurate load and then test softer/harder alloys looking for gains in velocity or the accuracy to drop off.
Anyway, yes a chronograph will give you numbers. What you do with those numbers is up to you.
SEE ! I knew I started coming here for a reason. Learn something new every day. Never before thought to test my tester. But I don't currently own a .22LR or a spring operated pellet gun. Now I got a good reason to tho. I recently got to the end of a box of test groups, (ten groups of five) the wide spreads didn't seem to corilate with the holey paper when the Chrono started actually adding shots to the groups, and blinking out. I got a spare battery, now I just need a spare test subject.
Just so you know, I have my original Chronograph with all its original parts intact.knox on wood
What he said. I learned the hard way! BTW, while you are at the range, there will always be someone who wants to shoot across your clock. NOT a good idea. If you want to give them a reading, do the shooting yourself AFTER YOU take a shot with their weapon at a target to make sure it will not splatter your chrono all over the place because their rig was not zeroed properly.
Last edited by murf205; 10-23-2018 at 12:59 PM.
IT AINT what ya shoot--its how ya shoot it. NONE of us are as smart as ALL of us!
A rubber band shot across the sensors generally gives a indication of operating, plus they are easier to keep on hand and cheap to replace
So what make and model did you get? One’s on my wish list, but haven’t decided which one to get. It seems prices are really coming down compared to a couple of years ago.
I've found my chronograph results to be pretty repeatable. Not exact, but close. Temperature, humidity and elevation make a little difference. What I don't know it whether a displayed speed of say 3000fps is really 3000fps? As far as clocking the same load in different guns, I would expect some differences. After all, every gun does not the share the same pet load.
"What I don't know it whether a displayed speed of say 3000fps is really 3000fps?"
With screen spacing of 2 ft or less it probably isn't. It will be relatively close though but still there will be some error. The higher the velocity the greater the error.
Most modern chronographs with "sky-screens" are quite accurate as such. However, there are some things many don't know. The shorter the screen spacing between the start and stop screens the less likely the displayed velocity is correct to the exact fps. All chronographs use essentially (Magno-Speed and LabRadar excepted) the same crystal timers. The crystal "timers" pulse only so many times per millisecond thus at a given velocity there will only be so many "pulses" in the distance between start and stop screens. The more pulses per distance the closer to the actual velocity the readout will be. The number of pulses is converted to time which is converted to fps. Shorter screen distances have less "time" between screens and thus when the time is converted to FPS the readout in fps is usually a round up or down. The longer the screen spacing the more "ticks" between screens so the closer to the actual fps the readout will be. A 2 ft screen spacing is more accurate than 1 foot spacing. A 4 or 5 ft spacing is more accurate giving very close to the actual fps if not the actual fps. A 10 ft spacing is about as good as it can get from a practical stand point giving the actual fps.
Also the chronograph read out is the fps at the center point between the screens, not the muzzle. That is why for any valid comparison (accuracy wise) it is necessary for the screens to be the same distance from the tested firearm muzzles (within reason, does not have to be exact down to the thousandth of an inch).
Last edited by Larry Gibson; 10-23-2018 at 03:21 PM.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
Have fun with it! Next thing you know you will have data from tens of thousands of rounds with temp ranges from 100+ degs to below zero, shelves full of 3 ring binders!
Charter Member #148
I have often wondered about the differences in the strength of the batteries as to the accuracy of the read outs. In other words, does the slightly weaker battery result in the crystal timer running slower that a new "hot" battery, or, is there a voltage parameter built into the circuitry.
IT AINT what ya shoot--its how ya shoot it. NONE of us are as smart as ALL of us!
I got the Caldwell G2 - it was on sale for $155.
I hear some gas checks have been known to shed at the muzzle and then pass right through a sky screen. Something to think about in that...though I have not yet experienced it...and am considering a very light gauge forward shield to reduce that inevitability. Cannot be too heavy a shield or blow back/bound back might be the result.
If it was easy, anybody could do it.
I have had questions about my chronograph as to accuracy and such. What has given me the most questions is the discrepancy between what my chrono gives me and what some of the loading manual get with their tests. However, I have used 22 ammo as a test and have other results that tell me there are discrepancies. If a powder company publishes a manual it seems like they are on the high side. I am taking barrel length into account. Also, I have a Speer manual that published some of their chronographed factory loads and I get within their ball park.
44mag is not all wrong. He mentioned lot number changes. Target shooters that used factory ammo would buy several boxes according to lot number. Same for reloader and powder lot #'s. When I talk about manual differences, I use the same components they list. You also have exterior factors like ambient temps and altitude.
Another issue. I have had more than a little statistical training in my college days. For some reason chronograph manufacturers now using calculators include standard deviation in their read outs. Sd is a mathematical concept used to compute t tests or z tests, etc to see at what level your results could be due to chance. In other words, if you go through all this you can determine if the results are 99% accurate or 95% accurate meaning there could be a 1% or 5% chance that they were just random. For our purposes, average velocity, average variation and the total difference are important. Also, a 5 shot sample is not all that accurate. Saying this I still often use a small sample and take my chances. You have to have something left over to shoot.
My chronograph has been fun and I consider it an important tool. I just used it to test the difference in results I might get with using Starline cases vs Winchester and for that load out of that rifle found them to be insignificant. Also I have loaded up some loads and wondered if they were giving me what I thought they should and have been either reassured or had my suspicions verified. I used it to test the differences between firing a muzzle loader with a clean barrel as opposed to a fouled barrel as we used to foul barrels in matches. It explained why. Even used my chrony to test shotgun loads.
As to other recommendations. Don't lend them out and don't borrow one. I bought one to replace one I borrowed. Take their advice seriously.
DP
I have never had GC smack the front of my chrono but I have had a shotgun sabot shed the slug and hit the face on my 1st Chrony. Amazingly it still worked but it had a pretty bad dent in the face. Since then, if I am going to clock a saboted round, I use a piece of 1/8" steel plate that I fabricated in front of the chrono.
IT AINT what ya shoot--its how ya shoot it. NONE of us are as smart as ALL of us!
One thing that was interesting was my friend was shooting his .223 near me and when he was firing, it would register but at relatively low velocity.
He was shooting 55 grn factory rounds which should be going in the 3000fps range and it would register in the 1500 fps range.
I am assuming it was somehow picking up the shock wave from the super sonic bullet or maybe the gasses trailing the bullet? Anyone know why this would happen?
What chronograph were you using? Sky screens the bullet has a some what narrow window to pass over to register. It may have been light angle throwing shadow on the sensors. Gasses tripping it would read faster. On the lab radar ive not had issues with shooters beside me being picked up, I do occasionally get a off reading from a wad being picked up in my BP loads. On my pact professional the smoke plume would give off readings or errors. Ive never worked with the Magneto speed but again a very narrow area for the bullet to be picked up.
I don't know, but it would be a Great question to ask Caldwell.
I have a Caldwell, although not the same type as yours , but have not had that issue with it... yet...
2nd Amend./U.S. Const. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
~~ WWG1WGA ~~
Restore the Republic!!!
For the Fudds > "Those who appease a tiger, do so in the hope that the tiger will eat them last." -Winston Churchill.
President Reagan tells it like it is: https://www.youtube.com/watch?v=c6MwPgPK7WQ
Phil Robertson explains the Wall: https://youtu.be/f9d1Wof7S4o
I’ve shot beside mine with it on and it doesn’t read anything.Caldwell or Chrono. I’ve shot thru both in series for test of readings and both are consistently on the money.
Posting Permissions
| BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
| BR | Bench Rest | M | Magnum | RN | Round Nose |
| BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
| C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
| HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
| PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
| LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
| GC | Gas Check |
Reply With Quote