|April - May 2000
Volume 35, Number
The Winchester Model 70 .264 Winchester Magnum is
I bought my first chronograph over
20 years ago from the Custom Chronograph Company, which has spent its life moving around
tiny towns in Washington state. This was back when many chronographs still operated off a
binary-switch system, and photoelectric light screens were just coming into use. I bought
the unit for two reasons: It was the cheapest ($89.95) light-screen model
listed in the 1979 edition of Handloaders Digest, and the company gave me a good
discount, though Id published only a few rifle-related articles in various obscure
magazines. These days $90 doesnt sound like much, but back then you could buy a box
of .30-caliber Nosler Partitions for $10, so any discount meant a lot to a starving
My Custom Chronograph Model 600 had
a rotary switch with 11 stops, each marked by a number. After the shot I turned the switch
through each stop; if a red light blinked on I recorded that number. Four would eventually
light up, say 1421. Id look up that number in a booklet and find my bullet had
traveled 2,843 fps. Then Id reset the chronograph by switching it off and on and
This might seem a tedious process
but was light-years ahead of the alternative: break screens. Used for decades before the
advent of photoelectric screens, most consisted of aluminum foil attached to paper
backing, the foil forming horizontal lines, spaced closely enough that a bullet would
break a line somewhere. After each shot both front and rear screens had to be replaced,
and you couldnt shoot groups at the same time, since the screen blocked the target.
Along with light screens, the Custom Chronograph Company included all the gear for break
screens, probably because nobody wanted them anymore. Aside from a single test the first
day I tried the chronograph when five Long Rifles from my old Marlin .22 averaged exactly
1,179 fps over each type of screen, I never bothered with break screens again.
Few shooters owned a chronograph in
those days. I did my shooting at the popular Deer Creek Range east of Missoula, Montana,
and never saw another range member using a chronograph, though a few asked to use mine.
The first was a guy with a .357 Magnum revolver. He took three shots over the light
screens, each indicating his 158-grain handloads were going about 1,300 fps. Hed
assumed they started 100 fps faster, so this almost ruined his day. After some grumbling
he moved as far down the firing line as he could, and probably kept on writing 1,400
fps on the labels of his .357 boxes.
I experienced the same
disappointment with some long-treasured loads. My small collection of centerfire rifles
included a .243 Winchester and .270 Winchester. The .243Õs deer load consisted of the
105-grain Speer spitzer, 41.5 grains of IMR-4350 and CCI 200 primers in Winchester cases.
The top load listed in the just-published Speer Reloading Manual Number 10 was 42.0 grains
for 2,995 fps (also using Winchester cases and CCI 200s), and Speers Ruger Model 77
test rifle had a 22-inch barrel, just like my Remington Model 700.
Five rounds fired over the photo
screens averaged a little less than 2,800 fps. This obviously wasnt right, so after
letting the barrel cool I tried five more. These averaged closer to 2,750. How could the
dozen-odd deer shot with the rifle have died from bullets plodding along like that?
My faithful .270 Winchester produced
the same disappointment with 58 grains of H-4831 and the 150-grain
Hornady. The year before Id
shot this load at 300 yards, after carefully sighting in 3 inches high at 100 yards. Four
shots (the last in the box) landed in a neat 1.25-inch group, centered 2.5 inches low.
(This was a very accurate rifle, three-shot, 100-yard groups with the same load often
measuring 1Ú2 inch.) According to the trajectory tables in my Hornady Handbook Vol. II,
this meant a muzzle velocity of just about 3,000 fps.
But the chronograph said the load
only started at about 2,850 fps. Just what was going on here?
Nothing but an old disease, known
among psychiatrists of the loading bench as Handloaders Optimism, known
as HO for short. (When chronic, as is frequent, the condition is called HO-HO-HO). Like
most handloaders who dont own a chronograph, Id pored over various
manuals and picked the highest velocity given for my loads.
Each load had killed a pile of game
out to 350 yards, as far as Id ever shot at anything. Normally both rifles were
sighted 3 inches high at 100 yards. Out to 300 I just held right on and the bullets landed
close enough to where I aimed, but on the few animals taken over 300 Id held
slightly high and killed everything neatly. So what did it matter that they started a
couple hundred fps slower? They worked!
It took over a decade for that
lesson to insinuate its way into my brain. Back then I felt compelled to work up loads
achieving 3,000 fps, using the 100-grain Nosler Solid Base in the .243 Winchester and the
130-grain Sierra in the .270 Winchester. They didnt fly noticeably flatter or kill
deer quicker, but I felt better, like somebody in a medical experiment whos given a
sugar pill instead of the real thing.
Since then Ive encountered other
velocity-impaired shooters, who seem to think super-speed bragging rights are the only
reason for ever shooting across light screens. A buddy called one day, not even saying
hello, just crowing 3,192! This was the supposed velocity of his favorite
130-grain, .270 load, just chronographed over a friends Oehler. On closer inquiry I
found 3,192 was not the average velocity of the load, but the fastest bullet in a
five-round string. I suspect, like my acquaintance with the .357, he writes the HO-HO-HO
number on his boxes of .270 loads.
More sophisticated chronographers
come up with other fictitious numbers. Perhaps the most widely publicized is standard
deviation, which to some not only bestows bragging rights but is equivalent to the Word of
God. According to one heavy dictionary, standard deviation is: Statistics: A measure
of dispersion in a frequency distribution, equal to the square root of the mean of the
squares of the deviations from the arithmetic mean of the distribution. Got that?
Having spent some of my university
life trying to make mathematical sense out of field work, I am somewhat familiar with the
odd science of statistics, enough to agree with whoever said, There are three kinds
of lies: lies, damned lies, and statistics. (Benjamin Disraeli sticks in my mind,
but my wife thinks it may have been William Gladstone. My 1955 edition of the Oxford
Dictionary of Quotations does not enlighten. If you know, please write me c/o Rifle, 6471
Airpark Drive, Prescott AZ 86301. This is trivia of vast importance.)
A few numbers-crunching handloaders
have proposed standard deviation (SD) as a measure of accuracy. Some even suggest that a
load with a low SD has great potential accuracy, even when it sprays bullets like
confetti. This notion has grown popular enough that many chronographs include an SD
function, including the inexpensive Shooting Chrony, which has done more to bring the
realities of bullet speed to everyday shooters than anything else. I am on my third
chronograph now, and second Chrony, for reasons that shall be explained later. My latest
model has an SD function.
How useful is it? Let me explain.
After three or four years of using this Chrony, Ive found about the same correlation
between standard deviation and accuracy as between asphalt and trout. Heres a
typical example, straight from my own .270 Winchester. While trying out some 130-grain
Hornady Spire Points one day, over a standard load of 60 grains of H-4831, I first shot
three times, getting a group of 1.66 inches with an average velocity of 3,015.66 fps and
an SD of 4.99. The SD was so low that I shot up nine total rounds of the load. Two more
three-shot groups went 1.45 and 1.87 inches. Average velocity for all nine dropped a
little to 3,011.2 fps, while SD increased slightly to 10.86.
Since this is normally a very
accurate rifle, I tried a half-grain less powder. Velocity decreased, of course, to about
2,980 fps, and SD increased to over 30, which is not considered too good by the
statistical ballistical crowd. Three, three-shot groups averaged just under an
How could this be? The reason is
very simple, and applies to almost all light hunting rifles. Normally a
good-shooting load involves bullets exiting the muzzle when the barrel is
bottomed out in its vibration cycle. Essentially, the muzzle is pointed in the
same direction each time a bullet leaves. Since the barrel pauses briefly at each end of
its vibration, even variations of 50 or even 75 fps (or SDs of 30 or more) often
dont cause groups to grow, but if the bullets exit while the barrel is whipping
around in midcycle, even small variations in velocity can result in large groups.
Another thing I have noticed with
this handy-dandy SD function is that often one five-shot string of a load will show a very
low SD, say under 10. So I try the load again and get an SD of 38, quite high. What does
this mean, especially when each group is essentially identical? The answer is, of course,
not a thing.
The real statistic applicable to
most hunting handloads is not standard deviation but reliability. Do the bullets regularly
group into circular patterns, or do fliers mar perfection? Do groups stay about the same
size, or does the rifle shoot into .5 inch one day and 2 inches the next? Does the rifle
shoot to the same place on Sunday that it did on Saturday?
Standard deviation is indeed a
useful tool for ammunition companies that must create consistent cartridges by the
hundreds of thousands, but home handloaders who cite standard deviation remind me of a
verse from the Oxford Dictionary of Quotations, chanced upon while trying to find that
quote about lies and statistics. It was penned by one Winthrop Mackworth Praed, who died
at the tender age of 37 in 1839:
Of science and logic he
As fine and fast as he can;
Though Im no judge of such matters,
Im sure hes a talented man.
With that well leave
standard deviation and go on to the really useful things a chronograph can do for your
hunting loads. Most importantly, a chronograph allows a basement handloader to create safe
loads. How so? Dont we need a pressure barrel to find absolute pressures? No, we
dont, because the bullet and powder companies who write handloading manuals use
them. While some list pressures, those are interesting but irrelevant to our needs. The
important statistic is velocity.
Heres why. The odds that any
given published load, even if duplicated exactly, will create the same pressure in our
rifle are probably 100 to 1. There are just too many variations in bore diameter, land
width and throat length (not to mention different lots of powder, bullets, cases and
primers) to expect 60 grains of H-4831 to produce the 51,700 CUP listed with a 130-grain,
.270 bullet in Joes Reloading and Cook Book.
But if we build various loads with H-4831 and
the same bullet in our .270 Winchester and find the powder charge that produces the same
3,050 fps listed in Joes book, were on pretty firm ground. Why? Velocity is a
very good indication of pressure. It has to be, since its the direct result of
pressure. While individual .270 rifles may vary slightly, theyre close enough for
the same pressure level to produce the same velocity. This has to do with a bunch of
gas laws, which, since it has been almost 25 years since I last sat in a
chemistry lecture hall, shall remain nameless. But given the same powder and bullet,
muzzle velocity is indeed simply another measure of pressure.
Heres how it works in whats
called Real Life. Last fall I had a custom 7x57mm built on a Remington Model 700 action by
Lex Webernick of Rifles, Inc. It has a 24-inch Lilja barrel and is superbly accurate,
partly because of the fine barrel, partly because of Lexs gunsmithing skill and
partly because it has a short throat. Most 7x57s are still built to accommodate antique
175-grain military loads, even though theyll never see one, with enough space in
front of the chamber to house a Norway rat. This long jump between case and rifling tends
to limit the bullets that will shoot well. The half-dozen 7x57s Id previously owned
all exhibited very persnickety preferences. Many would shoot one type bullet into one-inch
groups and everything else into 2 inches or more. Id always wanted a 7x57mm that
would shoot a wide range of bullets accurately, and Lex suggested the solution was a more
normal throat, so throated the chamber to accommodate a 140-grain Nosler Partition seated
to the base of the neck.
This, however, meant that standard
7x57mm loading data, worked up in longer throats, would be invalid. That really didnt
matter to me, since most 7x57mm loading data is wimped down to create a safety margin in
old military rifles, so doesnt apply to modern rifles. Instead I consulted 7mm-08
Remington data, feeling I was on safe ground because the 7mm-08 has about two grains less
capacity than the 7x57mm. Any velocity level safe in the 7mm-08 would be safe in a
short-throated 7x57. Data from various manuals, and my previous experience, suggested
Hodgdon H-4350 would get as much velocity out of the 140-grain Partition as any, while
maintaining that velocity in the subfreezing temperatures often encountered during Montana
The same manuals suggested 2,900 fps
or a little more would be realistic from a 24-inch barrel. From long experience, I knew
that long-throated 7x57s will handle 50 grains of H-4350 with 140-grain bullets, so I cut
that back 10 percent to 45 grains. A five-shot string produced 2,671 fps. Another grain
clocked 2,782, and 47 grains, 2,919. Eureka! Three-shot loads average around 5Ú8 inch in
calm air, which is excellent in a rifle weighing under 71Ú2 pounds with its 1.75-6x Leica
scope. Its excellent in any hunting rifle, and the brass has lasted through several
firings with tight primer pockets. (So far my experiments with other bullets indicate Lex
was right about the throat too.)
A chronograph also assures that
bullets will expand at longer ranges. While theres some variation (see Handloader
No. 193, June 1998, for Gary Sciuchettis excellent test), most expanding big game
bullets will expand readily down to at least 2,000 fps. If you might shoot a pronghorn or
deer at 400 yards, a muzzle velocity of at least 2,900 fps with most bullets assures good
expansion to that range. With some bullets 2,800 fps will do it. Last fall I hunted
whitetails in Arkansas and planned to test a new 140-grain, 7mm-08 factory load. The
velocity should have been at least 2,800 fps, even from the 22-inch barrel of my rifle,
but the Chrony indicated an average of 2,700 fps, which meant expansion might be iffy past
300 yards. I didnt plan on shooting past 300 anyway, and the two deer killed were at
75 and 140, but not relying on the catalog numbers made everything a little more sure.
With a chronograph you can also
rebuild a favorite handload more easily. Variations between powder lots can easily change
the muzzle velocity of a proven handload 100 fps or even more. One year I ran out of my
favorite .223 Remington powder and bought two more pounds. Until then this rifles
favorite load used 28 grains, for about 3,450 fps with the 50-grain Nosler Ballistic Tip.
I loaded up a few and found they not only wouldnt shoot worth a hoot, but they also
made lifting the bolt handle a trifle difficult. Lo and behold, the Chrony revealed they
were traveling closer to 3,700 fps! I dropped the powder load until the Chrony read 3,450
again, and accuracy was restored. Since then this simple operation has been performed with
new lots of a dozen powders.
There are a few little tricks to
owning and using a chronograph. I bought my Chronys after my old Custom Chronograph
coughed and died one day. I compared Chronys belonging to friends to more expensive models
and found them quite accurate. Unlike most other models, the various Chronys dont
require the screens to be mounted on a board, attached by wires to the main unit on the
shooting bench. The whole unit mounts on a tripod with the velocity read off a screen on
the front of the machine. My present model stores dozens of shots, providing an average
anytime I choose. I keep it on an old camera tripod, set up and ready to go in my loading
room, which really saves time at the range when compared to more complex models.
This did create one small problem
with my first Chrony, which quit working one day while I measured some .416 Remington
loads. Thinking the chronograph couldnt take .416 muzzle blast, I sent it back to
the factory with a letter explaining the circumstances. It came back a couple of weeks
later with a note saying I should probably store my Chrony where there was less dust in
the air, since a bunch had drifted in through the screen slots. After the Chrony people
shoveled the dust out the unit worked fine. Duly humbled, I have since placed a strip of
translucent Scotch tape across each slot, which does not affect velocity readings. The
tape even seems to help on sunny days, which, through reflections off speeding bullets,
often cause bad readings.
That Chrony came to a sad end one
day. As usual, I was testing several different guns, including a .300 Weatherby Ruger No.
1 and a .41 Magnum Smith & Wesson. Because of the blast of the .300, Id set the
Chrony 25 feet from the muzzle, rather than my standard 15. After shooting the rifle, I
picked up the revolver to test a new
load using cast 200-grain bullets. This .41 was sighted in for my standard load using
220-grain Speer three-quarter jackets, but I didnt think of that, or that the
chronograph was farther away than usual. So I was pretty surprised when chronograph and
tripod performed a backflip with the first shot. Yes, indeed, Id plunked my poor
Chrony right in the readout screen. Remember, students: Lighter bullets shoot lower in
most handguns. So far my new Chrony has avoided both dust and bullets.
What amazes me is the number of supposedly
serious handloaders who dont own a chronograph, when a Chrony can be had for about
the price of a cheap 3-9x scope. I know guys who own anywhere from three or four to
several dozen expensive sporting rifles, all scoped with at least $300 worth of glass, who
dont have a clue how their carefully crafted ammunition is really performing. The
probable reason is that a lot of them have advanced cases of HO-HO-HO and dont
really want to know.