Chrono-madness!

[44Blam]

I just got a Chronograph and wow it's fun! Now I want to know - how fast is it???

I chrono'd some bullets I loaded for my .308 and tested out some loads. Got pretty good results, looks like I can drive a 178 grn bullet about 2500 fps before it starts showing pressure signs.
I also chrono'd some factory ammo - it was very consistent...

I chrono'd some 45-70 rounds I made and was AMAZED at how consistent it was with a min of 1803 fps and a max of 1831 fps -- with a 405 grain boolit out of my Marlin 1895...

I also chrono'd this little Russian CZ52 pistol - that thing was driving 80 grn 30 cal bullets at 1450-1500 fps!

That's some fun stuff right there. It also made me realize that I likely will not be able to push a lead boolit 2500 fps through my rifle, but my bet now is I should be able to get 2100-2300 should be pretty doable and will also work the action the way it is setup right now.

Next weekend's fun is 308 lead and chrono rounds from my Redhawk... I bet the Redhawk is chunking 240s at around 1400 fps...BUT We'll see!

[Hossfly]

Just be careful if its one that you shoot thru, and is 10’ In front of you. Don’t ask how I know.

[country gent]

Another thing to consider is to use a .22 rimfire with a good ammo or a spring piston air rifle and the same pellets to confirm set up and accuracy each use. Either will give consistant results over time. A tin of pellets or brick of 22s set aside for this lasts a long time proving the set up.

[Bzcraig]

Another thing to consider is to use a .22 rimfire with a good ammo or a spring piston air rifle and the same pellets to confirm set up and accuracy each use. Either will give consistant results over time. A tin of pellets or brick of 22s set aside for this lasts a long time proving the set up.

Good idea!

[MrWolf]

Replace the metal screen supports with wood dowels. Another trust me..

[country gent]

Weall it only takes a few minutes to fire the test rounds, and when done you know the set up is good and the chrono is reading correctly, with the test 22 or pellets. Just a way to save test rounds to know all is well before shooting them

[Jackpine]

And don't loan it to any relatives. (another "Trust me!")

[44MAG#1]

You didn't ask for advice so since this doesn't cost anything take it as you will. Here goes, ANYTHING you chrono only means one thing. It is a ballpark figure. It is not written in stone and never will be. Your velocities will be an ever changing thing to some degree or another. You can chrono a given load in a given gun today and test the same gun and load a period of time later and get another average velocity far more, far more , far more likely than not. Change one lot number of a component and that will change the outcome. change guns while keeping barrel length the same and that will change the outcome.
BALLPARK ONLY, no matter whether you use a five round string, ten round string, 20 round string or a 1000 round sting over the chrono. It is an ever changing thing.
That is the only fact you will have. Ever changing. Anyone that tells you it is isn't being truthful.

Again I mean no hurt, harm or anguish by my post. I am only making a statement based on my knowledge, experience and/or belief or opinion only. I am not trolling, baiting or calling out anyone by my post that I have posted on this posted subject.

[tazman]

You didn't ask for advice so since this doesn't cost anything take it as you will. Here goes, ANYTHING you chrono only means one thing. It is a ballpark figure. It is not written in stone and never will be. Your velocities will be an ever changing thing to some degree or another. You can chrono a given load in a given gun today and test the same gun and load a period of time later and get another average velocity far more, far more , far more likely than not. Change one lot number of a component and that will change the outcome. change guns while keeping barrel length the same and that will change the outcome.
BALLPARK ONLY, no matter whether you use a five round string, ten round string, 20 round string or a 1000 round sting over the chrono. It is an ever changing thing.
That is the only fact you will have. Ever changing. Anyone that tells you it is isn't being truthful.

This is correct. I have done the testing as 44MAG described and got the results he mentions. I also tried different firearms with the same length barrels and got differences on the same day with the same batch of reloads.
All you ever get is a ballpark idea of what to expect.

[Larry Gibson]

44Blam

However, keep in mind some loads can be played in a smaller "ballpark". It is those loads we seek, those that win the pennant over the "season"...... those that are the most consistent game to game or as we do with the chronograph; test to test.

If you are serious keep good records of the loads including the ambient temperature at the time of the test. Also set up the chronograph the same distance from the muzzle or bench each time. Average velocities will indeed vary test to test simply because the measured velocity of each shot varies. That's why there is an ES (Extreme Spread) and SD (Standard Deviation) calculation for each test string which give the average velocity. All three of those (ES, SD and average) are merely calculations of the measured velocities. The more consistent the load is the less the variation of those three calculations will be.

The fact you will have, if you are consistent in your testing, is that you have a 95% probability the average velocity (if a 10 shot test was used) of that load (same brass, same lot of primers, same lot of powder, same lot of bullets, etc.) shot out of the same test firearm under the same test conditions will be close to the same. As mentioned, change any one thing and...well....you have changed something so different results should be expected. Also mentioned, match loads shoot well in most any firearm made for them. Many "known" regular loads also shoot well in most every firearm made for them.

I have been using chronographs since the early '70s and have chronographed thousands of loads. It has been enjoyable and definitely a learning experience. Enjoy the trip ahead.

[dondiego]

And don't loan it to any relatives. (another "Trust me!")

Don't loan it to ANYONE, period! Trust me.

[44MAG#1]

44Blam

However, keep in mind some loads can be played in a smaller "ballpark". It is those loads we seek, those that win the pennant over the "season"...... those that are the most consistent game to game or as we do with the chronograph; test to test.

If you are serious keep good records of the loads including the ambient temperature at the time of the test. Also set up the chronograph the same distance from the muzzle or bench each time. Average velocities will indeed vary test to test simply because the measured velocity of each shot varies. That's why there is an ES (Extreme Spread) and SD (Standard Deviation) calculation for each test string which give the average velocity. All three of those (ES, SD and average) are merely calculations of the measured velocities. The more consistent the load is the less the variation of those three calculations will be.

The fact you will have, if you are consistent in your testing, is that you have a 95% probability the average velocity (if a 10 shot test was used) of that load (same brass, same lot of primers, same lot of powder, same lot of bullets, etc.) shot out of the same test firearm under the same test conditions will be close to the same. As mentioned, change any one thing and...well....you have changed something so different results should be expected. Also mentioned, match loads shoot well in most any firearm made for them. Many "known" regular loads also shoot well in most every firearm made for them.

I have been using chronographs since the early '70s and have chronographed thousands of loads. It has been enjoyable and definitely a learning experience. Enjoy the trip ahead.

While you are most certainly correct about the "smaller ballpark" what i am referring to is the braniacs that try to make it sound that what they find out in a chrono session is a "fact" which you and I know is never true.
Run out of your favorite powder, run out of your favorite primer and buy different lots of the aforementioned components and then see. One glaring proof of what I am saying look at the loading manual over the years. If it wasnt we would just need one the rest of our lives. We know they have changed. So nothing stays the same. Look at your photo in your high school yearbook and look in the mirror now. Wake up call.
I have been chronoing since one had to mount their own skyscreens on a piece of wood or some type of metal, "Tepeco Industries", im sure you will remember them.
That was certainly many many years ago when we both were much much much younger.
Just trying to keep both feet of the new chronographers on the ground. Where they should be.


Again I mean no hurt, harm or anguish by my post. I am only making a statement based on my knowledge, experience and/or belief or opinion only. I am not trolling, baiting or calling out anyone by my post that I have posted on this posted subject.

[Larry Gibson]

44MAG#1

Well the OP didn't come across as a "brainiac" to me. Actually I agreed with you ("As mentioned, change any one thing and...well....you have changed something so different results should be expected.")

Since we're talking about what irritates us let me mention what irritates me..... when someone posts something like; "I chrono'd 21 gr of 2400 under a Keith bullet out of my Ruger BH today and it gave 1230 fps....same load out of my S&W gave 1195 fps......" And they expect some sort of affirmation as to their "test" for whatever they think it means. No other information or details......irritating to me at least...... Know what I mean?

Let's not drift this thread, ok?

Or how about "average accuracy"... such as when 5 groups of 3 or 5 shots are measured then averaged for an "average accuracy" ....... how many really expect they shoot an "average"? Bet it's not just chronographers who don't have both feet on the ground over that one.......

[44MAG#1]

I used the wrong word and shouldn't have called anyone a brainiac.
I wasn't actually meaning any one particular person but I meant that as a generalized comment. Meaning me and anyone else that acts that way.
I made a mistake that people would understand what I meant. But I should have known that too.
All is my fault.


Again I mean no hurt, harm or anguish by my post. I am only making a statement based on my knowledge, experience and/or belief or opinion only. I am not trolling, baiting or calling out anyone by my post that I have posted on this posted subject

[44Blam]

LOL!
Why is it that every step I take to trying to shoot cast .308 in an AR cause an internet argument?

Anyway, it is an exciting step. I've chrono'd jacketed bullets from my .308 and have some data and I have a load for that bullet that I found to be accurate.

The next step is to see if I can get some cast boolits with a similar weight to run through the same rifle where it has enough power to cycle the gun and maintain accuracy and avoid leading. My expectation at this point is to be able to run boolits in the 2100-2200 fps range with accuracy, but I will work up to it.

The thing that REALLY made me happy is that I have a load for the 45-70 that is a load I have found to have accuracy in general shooting (eg, I can shoot clays at 100 yards consistently) ended up to have a spread of 28 fps over 5 rounds and is a 400 grn boolit trucking along at 1830 fps. Based on the load, I was estimating it at 1800 fps and it is "reasonable" to shoot. I cannot get the same kind of accuracy though because I cannot shoot it from a bench, it has too much recoil...

[Larry Gibson]

44Blam

No argument, just discussion. 44Mag#1 and I are further discussing it via PM......just different view points is all. Stay excited about your shooting and what the chronograph is telling you. You have received some helpful suggests most of which were learned the hard way..... like shooting the chronograph..... Hopefully you won't reinvent that wheel.......

[Hossfly]

I’m just soooo happy we can have available a devise we can measure the speed of our projectiles, at the price of around $100. The numbers, not being perfect still mean something tho, just like thermometers you get different readings with different ones in the same pot of lead. I’m still amazed that chrono can time something moving at 3250 FPS, record,calculate,display,send to your phone etc. in that small of pkg. even tho I shot mine thru the top of back timer device it still works and very consistently. Still gives all data that it gave when new, lucky I quest.

[JoeJames]

I have learned a great deal from my chrono. For one thing it is a whole lot more important than I realized beforehand, that you should look very closely at what they were shooting when they got the published results, ie., what firearm, what barrel length, and of course what boolit? It really makes a world of difference. Example, in my Ruger BH 44 Special, I used the same weight of Unique = 6.8 grains, but with a Speer swaged .430" 240 grain swc it was @80 fps slower than with a .431" Oregon Trail 240 grain swc.

[rockrat]

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!!)

[metricmonkeywrench]

Picked up a chrono for Christmas and recently got the Bluetooth add on for my chronograph and couldn't be happier, no more excel spreadsheets, and everything is recorded on the device society tells me I must have. Guess there is a reason to have a smart phone after all

With my cohort in crime/mentor I am learning to interpret the data, sometimes top speed is not the desired outcome if the load is not accurate or consistant.

Right now I'm working a .38 125g Power Pistol (4in S&W Mdl-10) load that seems to shoot ok as a plinking load, but when analyzing the data I have what appears to be a powder burn issue driving my extreme spread and standard deviation up. So something to look at in my reloading process and material selection to work on to drive these numbers down. Not to compare but to remove a variable the same pistol shooing a wad cutter load is almost boring for Chrono data low ES, SD and Av Velocity across the board which is to be expected with 3g of Bullseye indicating I don't have any barrel/cylinder issues.