After 30 years my PACT Model 1 has finally quit working. I've tried new batteries and even checked with PACT to see if I could get the newer style sky screens for it. PACT says that my model is no longer supported for service or parts by them.

I have to buy a new one as I'm about to re-barrel my 6.5x284 and need it for load development.

Any recommendations?

I've had an Oehler for more than 30 years now and it's sill going strong.

Oehler 35P, the best and surest way to really know what in hell is going on!

quote:

Originally posted by 308Sako:
Oehler 35P, the best and surest way to really know what in hell is going on!

There is NOTHING out there that can compare to the Oehler 35!

We have tried everything, and none come even close.

Bought 3 last month for use in different locations.

+1

I've used the Oehler 35 for about 8 yrs.I would suggest that those using theirs build a C or D size battery power supply especially if you use the printer. roger

Oehlers are too expensive! I bought mine in the 80's for about $350. It has cost me about $10 per year to have accurate velocity data.

Shooting chrony any beta model with remote display. I wouldn't bother with the printer.

This is on Par with the pact

I also had a PACT that finally died. I replaced it with an Oehler 35P and am totally satisfied. I should have gotten an Oehler several years ago when I started having trouble with the PACT and avoided all the frustration.

This isn't rocket science and a chrono is just a timer...the recorded velocity is NOT an absolute measurement, it depends on the screen spacing and how many decimal places the timer is accurate toO and how good the calculator is and where the sun is and where you shoot from and where the bullet passes over the eyes and...and...and.

I have an Oehler 33 I bough when they first hit the market way back when and I have a early model Beta Chrony that's been to the factory a couple times because I killed something inside it. I use it more often because it's much quicker to set up, I have it setup on a camera tripod and I just walk it outside and start shooting.

I've set BOTH chrono's up one in front of the other and get readings within ~15 fs and any discrepancy between them depends on which is in front and how far apart they are from each other.

Any one thinking they are getting exact fs numbers is whizzing in the wind...it AIN'T happening...and you only have to look at the differences in the velo range and understand what that it means.

Get whichever one you want, they ALL do the same thing...measure ELAPSED TIME BETWEEN THE TWO PHOTO SENSORS...NOT VELOCITY...the velocity is then calculated to a specific decimal place and converted to f/s, and every conversion has it's divergences.

I like my Beta...I like my Oehler 33...I would like to have a Oehler 35 and a PACT and one each of the other several chrono's on the market...I LIKE TOYS to play with...get whichever one tickles your w**w**, they ALL WORK.

I have an Oehler and a cheap Chrony. I have used them both to take readings at the same time and readings were less than 50 fps difference. The Oehler is a pain in the ass to set up, requires three tripods, cables going everywhere, diffusers that are hard to assemble, etc. The Chrony is cheap, compact, runs for years on a 9V battery, assembles in minutes with one tripod. I use the Oehler once every three years. I use the Chrony one every week.

I've used my MagnetoSpeed twice. It doesn't require any screens or lighting. It clamps to the barrel. It works for me.

I don't own a place to shoot so I'm at a public range. There NO way I'd be able to setup those tripod units on the weekend.

I can't imagine any chrono beating the Chrony for price vs performance. I have had two since they first came out; first one a friend centered it with a 500 Linebaugh and he bought me a new one. Works great.

Personally, I have a CED Millennium, which works just fine. I'm not sure that it's any more or less accurate than any other, but it's reasonably priced, has a couple of features that I like and is convenient.

Seems to me the main issue with any chronograph's accuracy is how accurate the distance between the skyscreens is because it all boils down to Rate = Distance X Time.

The chronograph will measure Distance, and Time, and then calculate "Rate" according to that formula, and in my opinion, that calculartion is almost a no brainer for today's technology.

JFWIW.

Oooops! I screwed up the formula! This is what I meant to post! (Sorry)

Personally, I have a CED Millennium, which works just fine. I'm not sure that it's any more or less accurate than any other, but it's reasonably priced, has a couple of features that I like and is convenient.

Seems to me the main issue with any chronograph's accuracy is how accurate the distance between the skyscreens is because it all boils down to Distance = Rate X Time.

The chronograph will measure Distance, and Time, and then calculate "Rate" according to that formula, and in my opinion, that calculartion is almost a no brainer for today's technology.

JFWIW.

Well the Chrony has fixed distance photoreceptors so it is idiot proof.

I use a Shooting Chrony; it is a newer one, about 15 years old and is Green. I don't remember which model, but it is either the bottom one or one up from the bottom. You have to buy the remote button and cable to retrieve data. It works very well and has very few errors. It has the plastic diffusers.

Years ago, I had a very early red colored Shooting Chrony with cardboard diffusers. It had one more button than my newer one; you didn't need to buy the cable and remote button to retrieve data. That old one probably gave error messages over half of the time.

I have a green one; only one button; on and off. It rarely gives error messages and I don't use the diffusers unless in bright sunlight. I think my old one was red maybe. I only need the bullet speed; I can do math.

Thanks guys, luckily I have access to a lot of ranch land, at least one of which has a dedicated shooting range so setting up isn't an issue.

Pretty much everyone I talk to compares everything to the Oehler 35 so that's probably what I'll get.

quote:

Originally posted by Fjold:
Thanks guys, luckily I have access to a lot of ranch land, at least one of which has a dedicated shooting range so setting up isn't an issue.

Pretty much everyone I talk to compares everything to the Oehler 35 so that's probably what I'll get.

Right on ,Frank. I owned 3 different model Chronies ( TRASH ) before I got smart and got the Oehler . roger

When you shoot it (yes you will) the Chrony
can be traded in for credit on another one.
Before you buy anything else compare prices,
and your actual requirements. Buy a Chrony
and spend the difference on ammo.

quote:

Originally posted by Fjold:
Thanks guys, luckily I have access to a lot of ranch land, at least one of which has a dedicated shooting range so setting up isn't an issue.

Pretty much everyone I talk to compares everything to the Oehler 35 so that's probably what I'll get.

Frank, I wish you were in Houston, I would sell you mine. Unfortunately it is so damn bulky with all the tripods and everything else, shipping it is out of the question for me . . . life is too short to try and pack the thing up.

quote:

Originally posted by hawkins:
When you shoot it (yes you will) the Chrony
can be traded in for credit on another one.
Before you buy anything else compare prices,
and your actual requirements. Buy a Chrony
and spend the difference on ammo.

I've been shooting over my old PACT for 30 years and haven't shot it yet. I used to let my club use it for testing ammo during IPSC matches so I'm amazed that it never got shot by one of the pistol shooters.

I don't buy ammo, that why I need a chronograph!

quote:

Originally posted by MJines:
Frank, I wish you were in Houston, I would sell you mine. Unfortunately it is so damn bulky with all the tripods and everything else, shipping it is out of the question for me . . . life is too short to try and pack the thing up.

No worries Mike, I was just there last month but my PACT was working then.

I agree with Mike.

If I were in the firearms business and devoted most of my time to shooting and load work...I would have an Oehler 35. Actually I have considered buying one too. That said...for my load work-up time...I use a Pro-chrono (similar to a Chrony). Simple, easy to use, and quick!!! I have shot it in tandem with a Oehler and it has always been very close. Keep it on a Camera Tri-pod.

[URL= ]Pro-Chrono[/URL]

The "guts" (the 1 megahertz chip and counter) are all pretty much the same in both the cheapest and the most expensive machines, and are almost infallible, meaning that they reliably count and report exactly how many pulses occur between the start and the stop signals from the sensors (provided that they receive the start and stop signals from the respective sensors).

The real difference in chronograph accuracy and dependability comes in the quality of the sensors ("screens") and the accuracy and distance of the sensor spacings.

The wider the spacing, then the closer the imputed velocity is to the actual velocity. In other words, a 4-foot spacing (as can be used with the Oehler) gives you a more accurate reading than a 1-foot spacing by a factor of 4X.

Screen spacing error is also an important factor. A 1/8" displacement with a 1-foot sensor spacing results in an error of 1/96th, or a little more than 1%, whereas the same 1/8" displacement of a 4-foot sensor spacing results in only 1/384th error, or .026% error.

Perhaps surprisingly, it is not mismeasuring the distance between sensors which results in spacing error, but shooting "crooked" between sensors: If your Shooting Chrony is placed with either its vertical or horizontal axis slightly misaligned with the path of your bullet, then the bullet travels a greater distance between the sensors than it otherwise would, resulting in a lower imputed velocity. With a 4-foot spacing there is much less potential "axial" error.

The "wider" velocity approximation with 1-foot sensor spacing largely makes chronographing to determine velocity consistency (standard deviation) much less useful. If you're interested in low SD's, then you really do need a chrono with at least a 4' spacing.

But probably the most irritating feature of inexpensive chronographs is the relative insensitivity of the sensors, resulting in some number of shots which simply don't register, or register in error.

The inexpensive chrongraphs certainly have their place. If you use a chronograph only occasionally, don't require close accuracy, don't need to use it in dim light like late afternoon, and can afford to experience some dropped shots, then you're fine with the most basic, least expensive model. But if you require higher performance then you'll be frustrated with an inexpensive chrono and will regret not buying the better one the first time.

What you say is true, Stonecreek... BUT...how do you check your results to certify that the resulting velo was actually a perfectly parallel/perpendicular shot and represents the absolute value?

Once the shot is fired, there is NO WAY TO RETEST...you cant replicate the exact conditions, no way, no how.

What you said is right out of my Oehler 33 manual and relatively meaningless in the real world as there are just too many variables getting tossed about.

FWIW...I ran some tests way back in the bad old days, checking that same information. I still have the 3 lengths of conduit I used, 2 ft, 3 ft, and 4 ft, and I measured EXACTLY between the centers of the photo eyes, THEN OFFSET ONE EYE BY 1/8" 1/4" AND 1/2" on each of the conduit lengths.

NOT JUST ONCE or only one caliber...I did the testing with a 223, 220 Swift, 308, 30-06, 7mmRM and an long throated 284 Win 16" XP-100 with at least two different bullet weights per cal, while I was developing various loads.

I couldn't tell ANY difference in velos because the velo range was WAY IN THE HELL BEYOND the slight difference those small offsets made...the velo range ran 25-200 fs hi/lo, SD 10-70 as I remember...but don't call me to task...I don't have any data to substantiate...All my early chrono/reloading data was burned up by an ex-wife.

There's theory and there's real...sometime they go together, but not always.

I wish Oehler would develop an update for the 33 using some kind of electronics like WIFI so those dammed plug-in cords could be tossed.

Easy in theory...not likely in reality.

There is a new type of chronograph about to hit the market. If it delivers any where near what it promises it will be a game changer. Street price is said to be around 500$ if I am correctly informed. First delivery some time this spring so maybe you should wait just a bit before you go buy an Oehler 35.

Look at their web page;

http://www.mylabradar.com

They all work - the technology is well developed and standardized.

quote:

Originally posted by Ackley Improved User:
They all work - the technology is well developed and standardized.

Yup. It's kinda like buying a Cadillac. It's still got a chevy engine in it. What you're paying for is whistles and bells.

quote:

Originally posted by NONAGONAGIN:
What you say is true, Stonecreek... BUT...how do you check your results to certify that the resulting velo was actually a perfectly parallel/perpendicular shot and represents the absolute value?

Once the shot is fired, there is NO WAY TO RETEST...you cant replicate the exact conditions, no way, no how.

What you said is right out of my Oehler 33 manual and relatively meaningless in the real world as there are just too many variables getting tossed about.

FWIW...I ran some tests way back in the bad old days, checking that same information. I still have the 3 lengths of conduit I used, 2 ft, 3 ft, and 4 ft, and I measured EXACTLY between the centers of the photo eyes, THEN OFFSET ONE EYE BY 1/8" 1/4" AND 1/2" on each of the conduit lengths.

NOT JUST ONCE or only one caliber...I did the testing with a 223, 220 Swift, 308, 30-06, 7mmRM and an long throated 284 Win 16" XP-100 with at least two different bullet weights per cal, while I was developing various loads.

I couldn't tell ANY difference in velos because the velo range was WAY IN THE HELL BEYOND the slight difference those small offsets made...the velo range ran 25-200 fs hi/lo, SD 10-70 as I remember...but don't call me to task...I don't have any data to substantiate...All my early chrono/reloading data was burned up by an ex-wife.

There's theory and there's real...sometime they go together, but not always.

I wish Oehler would develop an update for the 33 using some kind of electronics like WIFI so those dammed plug-in cords could be tossed.

Easy in theory...not likely in reality.

It's been way too long since the Model 33 for me to remember, but the earliest Oehler chronographs used a 400,000 hertz chip, which obviously provides significantly lower velocity resolution than the 1MM chip. (It's like using a 2-foot sensor spacing as opposed to a 5-foot spacing). If you Model 33 was equipped with a 400,000 chip, then that would explain some of your inability to distinguish performance differences with varying screen spacings.

But more importantly, the loads you were using exhibited a somewhat greater SD than many loads do. I ran a batch (.308 Win/N135 powder) through my Oehler 35 at my last session which had an extreme spread of under 20 fps and an SD of 7 fps, if I recall. While these are instrumental readings and subject to a very small error with a 1mm chip and 4' screen spacing, by definition the velocity resolution is four times as fine as with a 1-foot spacing.

The error from shooting over the sensors "crooked" and thus inadvertently increasing the sensor spacing is also potentially somewhat greater with the shorter screen spacing. It is just like the difference in the sight radius between a handgun with a 2" barrel and a rifle with a peep sight on a 24" barrel -- the axial error is greatly reduced with the longer "sight radius", whether you're talking about gunsights or chronograph screens.

Now, is all of this important to the casual hunter/shooter who is simply curious about his loads? No, not if you are just as well off guessing what your velocities are as you would be knowing within a couple of percent of what they are. But if your goal is to accurately measure both velocity and velocity deviation and to accurately measure the velocity changes due to small increases/decreases in powder charges, then the greater accuracy afforded by the more expensive machines may be worthwhile to you.

I frequently work up loads for obsolete cartridges for which little data is available, or alternately, use powders in cartridges for which data may be unavailable. For example, just try finding dependable data for a 7x33 Sako using powders with didn't exist 5 years ago. When working with variables which are outside of normal parameters like this, you need a chronograph which gives you dependable and accurate readings.

If you want accuracy, Oheler. If you want convenience, then anything else works... sorta.

One thing to consider about the magnetospeed units is anything that attaches to your barrel will change harmonics and POI.

Really comes down to - do you want convenience or do you want accurate information?

quote:

Originally posted by Opus1:
.

Really comes down to - do you want convenience or do you want accurate information?

The real question is just how much or exact information do you need??
Yes, Virginia, I know some people weigh their cases to 4 or more places and cut little logs of 4350 in half to get exact loads but is that really needed? I mean other than to stroke their egos or make them feel a better person? Is it really that important to know that your bullet is going 3257fps rather than a mere 3250?
I've proofed my clunky, old Chrony against various of the higher priced spreads and have yet to figure that my velocities are any more of a guess than theirs. They do have one advantage over me however, they can brag about how theirs cost more than mine. Ergo, if it cost more, it's got to be better, right?

I'd go with the Pro Chrono. I have the old Pro Chrono Plus,bought it in 98 or so. Once in a while it has a light problem that causes it to miss a shot depending on the time of day. As far as accuracy goes, I can chronograph a load and zero it at 100 yards then set for 1000 and be on target.

If I had to replace it I'd get the ProChrono Digital and add the USB Interface kit.

Are others just as good? Probably.

"I've been shooting over my old PACT for 30 years and haven't shot it yet. I used to let my club use it for testing ammo during IPSC matches so I'm amazed that it never got shot by one of the pistol shooters.

I don't buy ammo, that why I need a chronograph! Big Grin"
If I remember you also shoot doubles and that means you NEED a chronograph. While I tend to agree with Saeed about the Oehler 35P the question begs to be asked why not another Pact.
Bill

quote:

Originally posted by Stonecreek:

Perhaps surprisingly, it is not mismeasuring the distance between sensors which results in spacing error, but shooting "crooked" between sensors: If your Shooting Chrony is placed with either its vertical or horizontal axis slightly misaligned with the path of your bullet, then the bullet travels a greater distance between the sensors than it otherwise would, resulting in a lower imputed velocity. With a 4-foot spacing there is much less potential "axial" error.

Actually that's not true. Simelar right triangles (ones which have the same angles) will yeild the same axial error.

Showing my work:

Assume an angle of fire such that the bullet will rise 2 inches per 12. Using the Pythagorean Therom, the bullet traveles ~12.165" for 12" screens ~48.662" for 48" screens. (Square root of the sum of the squares of screen distance and rise.)

.165/12=.014%, .662/48=.014%.

If you just keep working off what your calculator figures, you get .01379375% for both, and my display has room for more digits ...

Cowboy: Correct, insofar as it applies. However, if the axis of the screens is both tilted in the vertical axis and the horizontal axis, then error is introduced.

Further, one of the problems with the "flip open" chronographs like the Chrony is not only that its screens are rather close together, thus providing a coarser approximation of velocity, but also that if the screens are not parallel with one another in the vertical plane (either tilted toward one another or away from one another, depending on how precise the hinge stop is), then the distance the bullet travels between screens is either more or less than the prescribed distance.

The further above the screens, the worse the error (of course, this isn't too much a factor with the Chrony since you have to shoot pretty close to the screens to get a reading in the first place.)

In all seriousness, I own and occasionally use a Shooting Chrony, the cheapest and simplest one. It is handy and satisfies casual curiosity about velocities. When I'm serious about putting the fine touches on a load, or working with certain unknowns, out comes the Oehler.

CB Dan gave us some data to work with instead of vague "mine costs more" bullshit. Since you profess to be obsessed with precise data, why don't you tell us if all of the "what ifs" occur when using a Chrony, what is the percent of error? Assuming a velocity of 3000fps, how many feet variance would you have?
Curious minds would like to know.

quote:

Originally posted by wasbeeman:
CB Dan gave us some data to work with instead of vague "mine costs more" bullshit. Since you profess to be obsessed with precise data, why don't you tell us if all of the "what ifs" occur when using a Chrony, what is the percent of error? Assuming a velocity of 3000fps, how many feet variance would you have?
Curious minds would like to know.

Okay, sure.

At 3000 fps using a 1MM clock, there are 333.33 "ticks" as the bullet flies between the screens when they are spaced one foot apart (1,000,000/3000 = 333.33). Conversely, there are 1333.33 ticks in 4 feet. So, a one-tick "counting error", whether caused by inaccurate screen spacing or otherwise, amounts to about 9 fps with a one-foot screen spacing, but only 2.25 fps with a four-foot spacing.

There is some amount of random error in the timing of both the start and stop screens in sensing the passing of the bullet, lets say for discussion purposes about 4 ticks (although the more precise sensors of more expensive chronographs will have a smaller error than those of less expensive models). With a one-foot screen spacing those 4 ticks equal about 36 fps. But with a four foot screen spacing they only equal 9 fps. So the difference in "resolution" is around 27 fps difference in favor of the wider screen spacing -- again, assuming a sensor error of only 4 ticks.

In actuality, the sensor error of a machine like my little Chrony is likely two or three times as great as the sensor error of my more sophisticated Oehler sensors. So, the combination of sensor error and lower resolution amounts to enough error that I know not to rely on the Chrony when I feel I need more precise information (and I don't want to burn up a lot of extra load work-up ammunition with the ever-present dropped shots you get with the Chrony.)

But just as a deer a hundred yards from your muzzle won't know or care whether your rifle shoots within 1 MOA or only 2 MOA and similarly won't know or care whether your handloads are maintaining a standard velocity deviation of 12 fps or 40 fps, the inexpensive "chronographs in a box" do plenty well enough so long as you recognize their limitations.

There is more error introduced in your chronograph readings by the changing position of the sun and clouds than you can get by "introducing errors with angular shots over the screens. Add in temperature changes and you have only a close approximation of your true velocity.

The chronographs use by the manufacturers of ammunition are in a temperature controlled environment with artificial lighting to measure velocities with at least a constant error.

I would also like to add that the sensors on a Chrony are more of a photo eye cell. It has to be able to distinguish a bullet (or boolit) passing over it by way of contrast from the back-drop. I use mine all the time and the only time my Chrony will drop a shot is when I leave the plastic diffusors of on a cloudless day or when there is not suffecient light. When lighting is a issue, I simply place a halogen drop light over the Chrony appox. 3' high. This allows the photo eyes to see it more clearly against the diffusors.
The instructions tell you all this.

No big deal. No dropped shots either.