Oehler is the oldest and arguably the most respected
name in chronographs. Their Model 35P is the only one I'm aware of with the
extra third "proof" channel to tell you when a reading isn't accurate
and should be discounted rather than used.

I ordered up the Oehler Model 35P Chronograph complete
with sky screens and stands to hold the sky screens as well as the bar to
maintain correct spacing of them. Oehler provided this to me for six months
product testing and I liked it so well I purchased it rather than sending it
back to them after the test period was over. The Model 35P has now replaced my
old and much used PACT ONE chronograph and I must say I'm happy with the
replacement.

The Oehler came with a printer which greatly speeds the
process of recording data as I now don't have to stop and record each shot by
hand while on the range. I just note on the tape what the load and gun was and
move on and then can either place the tape section with the target sheet later
or record the data on the target at my leisure. I like that convenience. Now I
confess to having a bit of trouble getting a new section of printer tape to go
in a couple times but a reference to the manual that came with it quickly
cleared that up. If I could have seen what I was doing I might have figured it
out without the book but without my glasses I'm about as blind as a bat close up
and I didn't have them at the time. Yeah I know a poor excuse is better than no
excuse however. That's my story and I'm sticking to it. If you have any
mechanical aptitude at all or have ever put a roll of tape in an adding machine
or calculator you'll have no such trouble as I did. I really ain't that hard
even for me now.

If you question the value of the proof channel let me
tell you that several times I got readings that without it I wouldn't really
have know whether to attribute to a poor load or an inaccurate reading that were
resolved as a result. I personally like the idea of the proof channel. With my
old chrono I sometimes got such readings also and I never knew if it was a bad
reading or a really poor load that slipped in.

I have no way to precisely measure the accuracy of this
unit vs. any other unit or to ascertain it's true accuracy but Oehler does and
they have provided that data which I have reproduced below from their website.

I really like the extra long cables provided on the
M35P but have to confess I really don't care for the on/off feature of it. To
turn the unit on you plug in the start cable and to turn it off you unplug the
start cable. I'd prefer a on/off switch myself but they say it is a safety
feature to keep you from accidentally leaving it on after use and running down
your battery. Well yeah it'll do that of course but if ya are such a dunce as to
do that then ya deserve to have the battery run down. Besides I sometimes like
to turn the unit off during a testing session for whatever reason and would
prefer a switch even if they insist on the cable turn off also. Just a personal
hang up of mine and not a real knock on the product.

With my old chrono I often found lighting conditions on
my range to not be conducive to getting readings and some shooting sessions had
to forego velocity readings since the unit just wouldn't catch the bullets. I've
missed a total of one bullet fired down range thru the M35P so far and it has
had thousands fired thru it so far so I'm really pleased with the performance of
it. So pleased that as I said I sold my old chrono and bought this one from
Oehler. To me that is testimonial enough right there that it gets the thumbs up
and Graybeard Seal of Approval.

If you want all the technical specs and such and must
read them they are listed below right from the Oehler website. My user
observation is that the M35P is a real winner and I highly recommend it to
anyone willing to shell out the almost $400 it costs as of this writing. Sure
wish I could afford to upgrade to the M43 PBL system but that's out of my price
range.

 

SPECIFICATIONS

SKYSCREEN CHARACTERISTICS:

SCREEN SPACING:

Minimum spacing of 1 foot is allowed; minimum spacing
of 2 feet is recommended.

Spacing of 4 feet is suggested for high velocity rifles.
Spacing of primary screens

can be set from 1 to 15 feet; proof screen is always set
midway between primary

screens.

 

 

PRINTER:

The optional built-in printer prints with real ink on
standard 2.25 inch plain paper. It

prints primary velocity, round number, and proof velocity
as each round is fired. It

prints statistical summary of primary velocity.

 

 

TEMPERATURE OPERATING RANGE:

0° to 50° Centigrade, 32° to 122° Fahrenheit.

Systems typically operate at temperatures down to 0°F or
-18°C.

 

 

EDIT MODE:

An edit mode allows for instant replay of up to twenty
shots. During replay you can

omit questioned shots from the summary.

 

 

BATTERY:

A single nine-volt NEDA 1604 alkaline battery is
supplied. A fresh battery will

operate the system for up to 25 hours including 1000 print
lines. Internal battery

compartment includes space for spare battery.

 

 

CRYSTAL OSCILLATOR FREQUENCY:

4.0 MHz oscillator for 0.25 microsecond time resolution

 

 

ACCURACY:

The expected error on any one shot depends on both
velocity and screen spacing.

Typical errors are shown in the table. The table assumes
good light conditions, dark

bullets, exact screen spacing, and shooting through the
center of the SKYSCREEN III

window. Actual errors under your shooting conditions will
be reliably indicated by

the PROOF CHANNEL

You will typically see the above errors as differences
between the primary and

proof channels of a Model 35P as you shoot under
"normal" conditions.

Note: It's easy to claim fantastic accuracy with a
chronograph measuring only

one velocity. Who checks the claims? You know your
accuracy only with the

PROOF CHANNEL, or by using two chronographs on each shot.
We know

our chronographs are more accurate and more reliable, so
we invite you to

check each shot.

 

 

PROOF CHANNEL:

The system alerts you with a flashing display and
printed asterisk if there is a

significant difference between the two velocity readings.
Differences which trigger

the alert are shown for typical velocities and screen
spacings.

STANDARD DEVIATION

Professional statisticians have long preferred standard
deviation as the best measure

of uniformity. We admit, standard deviation is a dog to
compute. That's why

Oehler chronographs compute it automatically.

Before calculators and computers were common, people
used substitutes for

standard deviation. One substitute is extreme spread or
the difference between

fastest and slowest shots. Our chronographs include
extreme spread because

shooters expect it.

Lately a second substitute, mean absolute deviation,
has been resurrected. One

manufacturer promotes MAD as a new discovery and a miracle
answer to

measuring velocity uniformity. Like comparing chopped
steak to sirloin, mean

absolute deviation gets you by, but it's not as good as
standard deviation. Don't take

our word for it; ask any statistician or check an
elementary statistics text.

Contact info
for Oehler is:  

Oehler Research, Inc. P.O. Box 9135 Austin, Texas 78766

(800) 531-5125  fax (512) 327-6903