Home Forums Hunting & Shooting Ask The Gunwriters Chrono, Yes or No

IMHO you are wrong. I'd take the audette knowledge and no chrono any day rather than the other way.

It helps to be in the sweet spot, and I STILL strive for accurate powder charges in the middle of that spot....

HOW a chrono can figure drop is beyond me. They haven't figured out how to gauge accuracy either...

I own a 35P for years. I use it from time to time, checking MV to see where I am in relation to max, but that means I rarely use it.

Will be soon, trying to get to 1200 fps in a pistol load, but once I know where the charges lead me, I'll likely never use it again on that particular caliber...

Yep, do they kill better? LOL

Dave, I do what I call 'ladder' tests of velocity when I'm working up a new load or for a NEW rifle. I always start low and load UP to what I 'expect' to be max >>>then I load a couple/three more IN CASE my data is off. It's NO problem to pull bullets of rounds that are 'above' where I stop.

EACH step up has 2-3 rounds ready to check, first for ANY sign of pressure, then to compare velocity. It's always best to STOP in the bracket velocity known for the cartridge.

Some graph while shooting groups. If it works great, I always thot it too complicated for me and my set up.

Good Luck

Jerry

It cannot do it, but what you can do is chronograph at two known distances to get a true BC on the bullet you are using.

That will help make computer predicted drops much more accurate if the published BC is not representative of the true BC.

I know I don't I'd have to tell you that the best way is shoot and see what your drops are....(grin)

I consider one to be essential, without one you're just guessing what's going on with your loads.

I use to use one a lot but haven't for many years. I generally use Barnes bullets and their data at near max, play with bullet seating a bit tip and get all I need to hunt with. With my handguns I load my big bores moderately and my smaller bores a bit under book (usually Hodgdon) max and I am good to go as well. I do not partake in the long range stuff.

I don't use mine all the time but I do like to know where my loads are when compared to book loads or my previous loads.

It's also handy for loading actual velocity in the ballistic app.

I chronograph any load with which I intend to hunt--just for my own peace of mind.

Chrono for me, every time I'm developing a load.

Dave,

If you want to track velocity deviations, the most common, inexpensive light-screen chronographs don't cut it. They'll usually show an average velocity very similar to more expensive models, but the individual velocities of each round won't be very meaningful for figuring deviations. If you just want to know the average muzzle velocity of several rounds the cheap ones work fine, but their isn't enough space between the screens for valid deviation calculations.

What did we do before chronos? Ignorance is, or was, bliss, I guess. We trusted what was written in a manual or on a box of ammunition. The manufacturer would know, right? And we happily took those factory loads, or our reloads, into the field and harvested game. We killed game for years. And then some more years. And still more. All without the comfort of a chrono.



But then, chronos started coming down in price, and slowly, we began to buy them. And what was written in our reloading manuals or on a box of ammunition wasn't always true.

What did that mean? There were a lot of possibilities.

Our readings came from our own gun and chronograph, not the ammunition/powder company's equipment.
Companies used their own rifles or a universal receiver. Often, they were a different barrel length than our own rifle.
They used different cases, and primers, or lots of powder.
Even different bullets of the same weight.

Or it meant that our chrono couldn't accurately determine velocities!



But what did that mean?

If your favourite 180 gr. 30-06 load listed at 2700 fps at the muzzle, but chronoed at 2550 or 2600 fps, do you demand your money back? Or, if you're a reloader, stuff more powder in, to bring it to 2700fps? No! And especially NO, if you've been using that load for years and taking game. Because, regardless of the velocity displayed on the unit, the load worked.



So what does that mean?

It means having a chrono is not a requirement for reloaders or anyone else. They are a fun to have toy, unless you are in the business of having to know. And of course, if you have to know, you buy an Oehler!

Thanks again for the brain waves, gang.
MD, I'm not sure if I really will need SD calculations for my needs, especially now as the shakes are a factor, but it seems like a hun or two to keep me safely away from the Stupid Zone isn't a bad investment. It will be kind of like how I used to use mileposts, second hand, and the tachometer to tell my speed when I was too poor to buy a speedo cable. Or, if both were broken -- I still knew how fast I was going in each gear.

I had an Oehler 35P. It was the worst chrono experience I have ever had. My current chrono, Magneto Speed, is the best I've used to date.

NO ONE can have my O 33 ! ! !

Jerry

Reloader28,

Interesting. I have half-a-dozen chronographs, but my Oehler 35P is the one used when I absolutely have to know exactly what's going on. As far as I know, the same is still true of Bryan Litz, and I have yet to visit a professional ballistics lab that doesn't use an Oehler.

One of my others is a Magnetospeed, and while it provides very good information, I much prefer the ability to shoot groups and chronograph at the same time. Dirtfarmer and annother friend use stands for theirs, which I might eventually do, but since I mostly chronograph on a private range there's no particular advantage to the Magnetospeed over my 35P.

I view my chronograph almost as a novelty anymore. It gathers so much dust I ought to sell it. I don't skate on the ragged edge of performance anymore (ie: I'm happy with 1800fps cast bullet loads in my '06's for target shooting, and I load 40gr. 4895/165 bullet for hunting, when I actually hunt with an '06), and SD, ES, FPS, and erectile dysfunction don't concern me either. 90% of my shooting is at 100yards on paper, and truthfully about the only times I drag the chronograph out is when I think I might talk about a rifle/load where someone will be sure to ask what velocity that load is getting. A simple day at the range necessitates a trunk full of gadgetry as it is without having to throw a chrono, sky screens, and tripod in there too- it takes up as much space as a case of whiskey (which is a much better arbiter of velocity for internet velocity claims).

When I experiment, I swear 200 lb of gear gets loaded into my truck. Chronos (2, in case one malfunctions), a large range bag, spotting scope, a box with my gunsmithing tools, a separate cleaning kit and rifles.

It's a royal pain. So much nicer to throw a box of ammunition on the front seat with a rifle and go make some noise.

Apparently folks view chronographs in different ways. I see one as the single best way for reloaders to stay out of trouble. Dr. Howell described handloading as akin to riding a bicycle close to the edge of the Grand Canyon at night. You can sort of know you're getting close to going over the edge but you don't really know where that edge is. A chronograph sheds much better light on where that edge might be.

Velocity and pressure are not a 1:1 correspondence but they are very closely related provided one is using a powder reasonable for the task. It is not exact in that X fps = Y psi, but if used properly with some common sense velocity readings can act as a series of warning lights to tell you that pressures are green, yellow, amber or bright red with a pretty large degree of confidence. Used in conjunction with good pressure tested data a chronograph is a better indicator of what's going on in the combustion chamber than all of the "pressure signs" ever dreamed up. Of course, if the rifle flies into a thousand pieces, that's a pretty reliable pressure sign....

Without going into a long treatise of how to use one to best advantage, I can think of two times in particular when a chrono was the only thing telling me something was definitely wrong.

1. Worked up a good load in a .270 and .300 WM with RL-22, velocities were as expected for the charge weights used - which were not absolute max. After finishing up an 8 pound keg I bought another keg from a different lot. Using the exact same charge weight velocities were 200 fps faster - about 3300 for a 130 grain bullet in the .270. I have no idea what actual pressures were except that they were "really high". I had to back off several grains with that lot of powder to get back down to a reasonable velocity for the cartridges.

2. Just recently I had a .243 AI whose accuracy was going south. I figured after 2300-2400 rounds that barrel was getting toasted. I chrono'ed a fireforming load which should have been a mild load in a standard .243 and velocities were almost 250 fps above what they should have been. Again, I have no idea what the actual psi was, just that it was way beyond a safe working maximum. A tight patch and brush down the barrel found a very tight spot indicating a major buildup of copper just ahead of the chamber. After cleaning thoroughly velocities dropped back down to normal and accuracy returned to normal as well. Without a chronograph I never would have known that pressures were slowly creeping toward a KB. Link to original thread about this


If someone wants to read a lot into SD's, maximum spreads and stuff that's fine, too. They can give you data beyond what's on the target to find an optimum powder and load, but the single biggest benefit to me is simply knowing the actual velocity in any particular rifle in relation to what should be expected and telling me with a fair degree of confidence that my load is Safe, Getting Close to Unsafe, or Whoa!

Even though it wasn't one of the items I mentioned when I first started the reloading investments thread, later on when someone mentioned their Magnetospeed I definitely agreed with it being an important tool.

Granted, I don't use it all the time. More so with some rifles/cartridges than others. But pretty much every load I am serious about gets chronographed at some point.

I used it just last night on a new 223 load. Rifle is an 18" Encore in 223, using the excellent Sierra 1365 and Benchmark. I loaded up a ladder and shot it when I got off work. Took the results home and studied it a bit, used that data to roughly identify low and high node. Went to the bench and loaded 3 rounds of each. Since my range is only 2 miles from my house on private land, I ran back over there and popped the rounds of real quick to see where in the ballpark I was. Both fell right in track with where I thought they should be and that helped give me confidence I was looking in the right areas to continue my accuracy testing.

One of the reasons I load is to produce ammunition that does exactly what I want it to do. Travelling at the proper velocity is one of the parameters I look for since impact velocity has such a great effect on terminal ballistics. It seems most folks want to know the bullet speed for external ballistic drop charts, but then neglect terminal effects. But both together form the big picture. For target shooting terminal is irrelevant. But pretty much all my rifles are called upon to hunt on occasion, even the ones I do LR and target shooting with.

There may be more accurate chronographs than the Magnetospeed. But especially in the wind we have around here I will NEVER go back to a chrono with skyscreens again. They are such a PITA. Tricky setup, missed shots, wind blowing the screens over, lots of gear. The Magnetospeed is so simple, so easy compared to that. At some point the Lab Radar could be a viable option for me as well. It sure would be nice to be able to grab the speed data while I was shooting ladders. But right now it is out of my price range.


And EDIT to add, that was an excellent post Jim. That is exactly why I use one a fair amount. Primers, bolt lift, that kind of thing has always been kind of like reading tea leaves to me. Actual velocities gives me one more tool for me to use to make sure I am staying safe.

Jim in Idaho posted the following above.

"1. Worked up a good load in a .270 and .300 WM with RL-22, velocities were as expected for the charge weights used - which were not absolute max. After finishing up an 8 pound keg I bought another keg from a different lot. Using the exact same charge weight velocities were 200 fps faster - about 3300 for a 130 grain bullet in the .270. I have no idea what actual pressures were except that they were "really high". I had to back off several grains with that lot of powder to get back down to a reasonable velocity for the cartridges."

Jim I had the EXACT same thing happen to me back in the 80s. I was using H 4831 <before changes had begun to show up > I had been shooting 62 grs under 130s for a LONG time. WELL, well with ONE new lot my velocity jumped + fps. - the bolt was STIFF, I didn't have to beat on it but it took a lot of effort to lift.

I KEPT that lb - lot # 9 1 81. I plan to xperiment with it and REDUCE the charge to get back to 3100 fps, but haven't done it yet.

At the opposite of the end of spectrum. I had a LOT of a popular/respected BRAND of brass, also for 270. I LOST 200 fps in that BRASS alone.

W/O a chrono I'd have never known or figured out what the problems were.

Jerry