I would be interested to hear about how you use your chronographs. Do you use it to compare your velocities to published? Do you use it to look at the spread or standard deviation of your handloads? Do you use it as a surrogate for pressure? Others?

Thanks,
Doug

I use it for all of your questions. Its priceless for what it offers to handloaders. Interesting to see just what factory loads produce. Also it certainly validates what a handload is producing as far as velocity, and velocity deviation. Also the impact that cold weather has some handloads. I think I will always remember the moment when I fired my first round through the screens and there was the velocity reading on the meter - when you get to be 57 years old there is very little left that amazes you - this was one of them.

All of the above, plus....

Velocity is a decent indicator of fouling and sealing with cast bullets. For example, if I start out with a clean barrel, I expect a good cast bullet load to maintain a consistent velocity over a string of 15 or more shots (with the possible exception of the first shot). If the velocity goes downhill as more shots are fired then the barrel is probably fouling. I find this is more reliable than visually inspecting the barrel because the naked eye cannot always see the difference between normal fouling vs. "problem" fouling.

I also use the chrongraph to judge gas sealing with different cast bullet lubes, alloys, diameters, etc. It is not unusual to see 100 fps or more difference in velocity just by switching lubes in otherwise identical loads. I have reason to believe this is due primarily to changes in the gas seal, not changes in friction .

Most of the year I use them as doorstops...but I have also been known to use them to weigh-down parts while the glue dries on plastic models.

During the three weeks of decent shooting season, I use them to measure bullet velocity.

When I am working up a new load, I use both the chronograph and the strain gage.

I make cartridges in matched pairs from the lowest recomended load to the highest, and plot both peak pressure and muzzle speed vs. powder charge. I also run a third graph of muzzle speed vs. peak pressure.

From the three graphs, it is a cinch to choose the load you want.

quote:

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Originally posted by denton:
From the three graphs, it is a cinch to choose the load you want.

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Denton, You've been nice enough to try to convince me on the use of chronos before, and
sure I'm a bit thick. However when needing to
waste some more money I went for a new press
instead. For loads, I go for reasonable performance as stated in a few loading manuals,
and then zero in on accuracy.
Using the powder I want to get rid of, I'll take
some loss of Vel. but won't take a serious loss
of accuracy.
Regards John L.

Doug,
There's been times i used mine for a target, but that wasn't intentional!!

Since I use load books and quickload, i use them to verify what my gun is doing.

that is, to verify the vel's quickload offers.. and the use as a guideline between the obeserved pressure signs (not that i can "read" anything other than "too much" or "room to go" "this looks okay". in relation to what quickload says...

i have just this little theory that says if quickload is pretty close in vel, then the equation should hold true that the pressure is about right.

When working up loads, I write EVERYTHING down, especially results... after all, you are after results.

youwould also know quickly if you had a pressure JUMP, with the corrosponding jump in velocity.

Myself, I feel that one can not create a truely accurate loading model without one

then again, I an ubergeek!

jeffe

JAL, not everybody needs a chronograph. There are a lot of people for whom such a device would be a waste. If you have answers to the questions that bother you, then, I don't think you need one. I use mine about twice per new gun, as I "bring up" new loads. That's not a lot of use.

I use mine to measure the velocities of my most accurate loads. It is not really a "surrogate" for measuring pressures, but can give some very broad indications of pressures.

How do I use it?
1. decide that I want to know what a particular load is actually doing velocity wise (the target says the rest).
2. set up my target(s)@ 100 yards.
3. set up rifle in rest and on target.
4. step up chrony (making sure bullet passes over sensors, not thru chrony)
5. test, record data etc.


Load books provide figures based upon their tests. Odds are their weapon is different enough that their results won't match my results. My experience confirms that.

Sure, and I love gadgets.
But my stumbling block is, just what do you do
with your vel knowledge.
I have some figures from a friends chrono, so now what? . They were in the ball park to what
one would expect, a bit low on one no doubt due
to the 20" barrel, but what can I DO about that.
Same with my 20" 3030 m94. Factory Win.S/Tip boasts 2400. The chrono says 2200 appx.
All I can do is "lump it".
What I did do with the 20" 223 when trying a
slower powder was compare the bullets traj. at
100 then 300 yds. I reckoned similar drop showed similar Vel?
And I like the one about keeping a record of
things (as I do) Could come in handy at the
coroners inquest :-)

Well, you COULD use the velocity figures to predict downrange performance, but of course you STILL have to actually shoot at the longer ranges to know for sure what's REALLY going to happen down there!

I use my chronograph each shooting session which is three days a week, weather permitting. I shoot several of my rifles, rifles of buddies, and take a friend who is retired and builds rifles for a hobby. I have a private range (100 yd and 200yd benchs) so setup is no problem. When I buy a new rifle I check the books, determine what powders and bullet I want to try, load up three at a time until I get what I want in accuracy and speed then tweak until final load. While knowing the speeds are important, knowing what the loads do at distance beyond my two hundred yard bench is also of utmost importance. 350 yards are as far as I need to shoot at game but I will play farther with targets. The chronograph plays an important role in telling you speeds, but that bullets behavior at those speeds down range can be found only from shooting. ----- I hope I said that as clearly as it is in my mind, sometimes my words cannot relate what my mind thinks. Good shooting.

I have a 1903 Springfield 06 that still had the original 2 groove bbl. It was quite accurate but the velocities resembled those of a 300 savage. Nearly 200-300 fs under par. The rifle now wears a new bbl, still shoots very accurate and gives the 2750 fs with a 180 gn bullet that a 30-06 should give.

If not for a chronograph my bullet drop @ 350+ yds would still be considerably more than it should be and I may not even know about it. It is amazing just how much velocity variance there can be among rifles. Knowing is a good thing.

quote:

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Originally posted by JAL:
Sure, and I love gadgets.
But my stumbling block is, just what do you do
with your vel knowledge.
I have some figures from a friends chrono, so now what? . They were in the ball park to what
one would expect, a bit low on one no doubt due
to the 20" barrel, but what can I DO about that.
Same with my 20" 3030 m94. Factory Win.S/Tip boasts 2400. The chrono says 2200 appx.
All I can do is "lump it".

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JAL,

I tend to agree. I think the chronograph can be useful but I don't think that I have been able to tap fully what information I can get from it. How do I interpret higher than normal standard deviations in velocity for a given load (also, what is a "normal" or reasonable standard deviation)? In some situations, I can't seem to reach close to book published velocities with equal charge - is my bore slightly larger? Barrel length differences between what I shoot and offsets in velocities won't explain it.

Basically, I would like to see a good treatise on methods of using a chronograph and ways you might be able to troubleshoot loads by gathering data.

Thanks for everyone's thoughts,

Doug

I'm a pretty conservative handloader. What I do when working up a load is to increase the powder charge until I reach either the published velocity or the maximum book charge. If I reach the maximum charge but am not getting book velocity then I try another powder. I'm not sure my method is any good but I feel it keeps me in a safe range.

Jeff

The Chrony separates the "Liars from the Bullshitters", and the "Optimist from the Realist."

For all the reasons already cited I can't imagine a serious shooter/reloader that doesn't use a chronograph. Without it you simply don't know what your load is doing much less how to go about developing anything better. Before the chronos were readily available folks just guessed and sometimes actually got lucky.

quote:

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Originally posted by JBD:
For all the reasons already cited I can't imagine a serious shooter/reloader that doesn't use a chronograph. Without it you simply don't know what your load is doing much less how to go about developing anything better. Before the chronos were readily available folks just guessed and sometimes actually got lucky.

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Sir, depends on what you call serious. First up
all the "pressure" people say don't go over book
max. So with that motherhood statement we are
somewhat limited no matter if we had a setup to
rival Hodgdon.
Then, these well known experts, (the reloading
manual people,) always know more than us.
This also tends to crimp our style.
Next, I have access to a chrono, but don't know
what to do with it. For years now, with the help of good manuals, when a friend shows off
his new chrono, I usually go on record and guess
the vel. Yep you've guessed it. I'm dammed
close.
And, my loads do quite well thank you.
At 900 yards when the markers tell me the bullets are going through sideways, I don't need
a gadget to tell me there needs to be a bit more
powder on board. Not to mention comparing drop
settings with other shooters.
Bullseyes count.
With hunting, well if the critter dies real
sudden, and the drop figures over the longer
ranges matches factory figures, well, don't get
your hackles up, but this serious handloader
doesn't care if I can't produce a printout of
last years shooting at air between the screens.
Serious is it, I just bought my 4th. press.
John L. ;-)

I check the velocity for my loads.

In my 375 ultra I tried R-22, IMR 7828 and IMR4350 I worked up loads with all three and the IMR 4350 had the highest velocity by 150 FPS.

Then in my 300 ultra I tried IMR7828 R22 and Retumbo. This time Retumbo had the higher velocity. Again @ 150 fps.

I would never have known this without the chrony.

JAL, I am honestly very glad you are so satisfied without a chronograph - really I am. However, I personally am not. My guesses about how fast my bullets travel have been way off in some cases. I usually end up developing loads for about 3 to 4 new rifles a year and have learned I simply cannot guess even close in some cases. Since you can sir my hat is off to you. However, please allow the rest of us mere mortals to use the machine. I mean even you admit resorting to the largely irrelevant chronograph on occassion to confirm what you already knew. Now I realize this does NOT APPLY to you, but I stand by my original statement to the effect that most serious reloaders need and use a chronograph for a multitude of reasons. Have yourself a nice day.

When I first got my 300 WSM, there was almost no loading data for it. Only source was the winchester website for ww760 powder. I wanted to use H4831SC so I ventured into unexplored territory, by interpolating 300 win mag loads reduced by 10% and worked up to what velocity the wsm was supposed to do. I never found WW760 to be worth a damn, but loaded some with it just to see if it would work.

Without a chrongraph, I would never have done the H4831 loads, but I could watch as the velocities climbed in even increments for each grain of change in the powder. When the incremental climb flattened out I knew I was at max.

The 760 loads showed pressure, less gain per grain, and no where near the top velocity. It runs into pressure before reaching top velocity. Again I wouldn't have known that without the chrono.

When working up loads for long range work, I want a load that's as consistant as possible. Meaning lowest extreme spreads in velocity. Working over sky screens lets us check groups at the same time so we get an idea of overall accuracy. Now sometimes the best groups are not the most consistant in extreme spread. Same goes for best extreme spreads are not the best groups. Occasionally I get both at the same time, then it's time to back away from the target to see if the groups stay small at 200, 300 or more.

Knowing velocity lets you make a better guess at drop at longer ranges. Using the data at the back of most loading books gives trajectory info for known velocity. Going with what the book says you're SUPPOSED TO GET, can result in too much drop if you end up a lot less velocity than what the book says.

quote:

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Originally posted by JBD:
Since you can sir my hat is off to you. day.

---

Whoa, I only meant that I use various reloading manuals as a base to work up loads. Then allowing for a few varables, I've found the better manuals about right. And why shouldn't
they be? Gee you blokes must have nightmares
on how your documented loads loose speed with
distance. I'm sure some people get too immersed in the detail, but if your hobby is
"figures" well good day to you to.
John L.

quote:

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Originally posted by grizz:
snip

When working up loads for long range work, I want a load that's as consistant as possible. Meaning lowest extreme spreads in velocity.

snip snip

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Grizz,

I don't want to be critical but your above comments just supports where I am at. I set up the chrony and throw five rounds thru and see some variability in velocities. But, I don't know what "low" is. Is a measured standard deviation of 100 ft/s low? 50 ft/s? Once you define a "low" standard deviation, how do I troubleshoot why I am above that range of standard deviation? Variation in powder charge (I have an electronic scale - Lyman 1200 DPS that dispenses powder to a reported accuracy of +/- 1/10 grain)? Bullet runout?

See my point?

Doug

I use mine during load development. I will pick a cartridge/bullet/powder and load them in 1 grain increments from low to high using what ever source for the loads. I will load 3 rounds in each 1 grain increment looking for signs of pressure on the case and at the same time looking for velocity spikes and plateaus. I generally see a some what consistant raise in velocity between each step until a plateau is reached then along comes a spike. But not always. Anyways, I figure the point before the plateau is about the maximum for the load. I don't know where I heard of this method. Perhaps it just came to me. I doubt it since I have never had an original idea.

Well join the club re.original thoughts.
And I also have read quite often about the Vel
leveling out.
After asking so many for so long I'm starting
to get some stuff into my head, and maybe this
use of the chrony is enough reason for me to buy a cheap F1 one day.
I was wondering what to buy next. . . because
those electric scales aren't worth having. . .
are they? :-)

quote:

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Originally posted by douglast:

quote:

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Originally posted by grizz:
snip

When working up loads for long range work, I want a load that's as consistant as possible. Meaning lowest extreme spreads in velocity.

snip snip

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Grizz,

I don't want to be critical but your above comments just supports where I am at. I set up the chrony and throw five rounds thru and see some variability in velocities. But, I don't know what "low" is. Is a measured standard deviation of 100 ft/s low? 50 ft/s? Once you define a "low" standard deviation, how do I troubleshoot why I am above that range of standard deviation? Variation in powder charge (I have an electronic scale - Lyman 1200 DPS that dispenses powder to a reported accuracy of +/- 1/10 grain)? Bullet runout?

See my point?

Doug

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Doug, you're mixing terms; extreme spread and standard deviation are totally different terms. For example, in a 30-06 case,(or one of it's children, 270, 280), an extreme spread(ES) of 75 to 100 fps is a lot, or high. For my standards, I don't want to see an ES of more than 25 fps. If I see an standard deviation(SD) of more than 10, there's something wrong with the load. Either the powder burn rate is not what it should be, or the bullet is wrong for that powder.

How I've learned to interpret what SD says about a load is thus; It's a statistical representation of how to predict what the velocity is going to be for whatever load you're using. If a SD of 10 is given, then any one shell in the box will be within 10 fps above or below whatever the average velocity was for that load. It's darn near useless for 3 shells, almost the same for 5, ten or more is a better guess. My pact chrono does the SD calculation when you are getting the group summary at the end of the string of shots.

For long range at 600 or better the low ES and SD loads will group better in the vertical plane. High ES shells will have a long narrow group in the vertical plane, no matter how good they look at 100 yds.

Mann, that's what I was talking about, and I'm right there with you on the point just before the plateau is where the max should be for whatever combo the load consisted of.

Sorry John L. I just had to pull your chain a little bit. Seriously, if you will just get a chronograph you might really come to like it. There is just too much variation in component lots, rifle chambers, barrels, etc for you to be doing anything but making an educated guess about what is happening without that chronograph. Your actual results may be and often will be dramatically different from what the book is listing. Note that the books themselves often dasagree on what constitutes a top load or what components deliver the best results. It is not like we are talking big money here. The basic Chrony is cheap and does an excellent job. There is a lot more to be learned here than just how fast your load is going. Good shooting to you and absolutely no offense intended.