Guys,

Some recent posts have caused me to think I may be a dinosaur, and that it may be time to replace the Oehler Model 33 I bought in 1985.

Other than occasionally putting a bullet through the Skyscreen, it still works fine and all I have ever done is change the batteries. It simply gives me all the data I have ever really needed.

Still, I cannot resist progress. I have skipped several generations of chronograph technology and now need to know:

What's the best chrono out there right now?

Here are some criteria, some are "must haves" others negotiable.

1) Separate screens and display unit. See note on Skyscreens above.

2) Shotgun friendly. Again, note on Skyscreens.

3) Easy set up and minimal supporting structure. A tripod is about as much trouble as I'd want to go to.

4) Computer interface, wireless capability is a plus.

5) Cost? Not sure it matters. I got almost 30 years out of the M-33, God help me to get another 30 years out of the new unit.

I am actually considering one of the higher end personal ballistics lab kind of set ups where I can generate pressure data as well as velocity. Anyone up to speed on these systems?

Thanks in advance for your insights.

I have a PACT personally, but the dual channel Oehlers are still my favorite to use. They were just priced out of the popular consumer market.

Oehler lists the 35P complete system for $575 plus $20 shipping.

__________________
Science plus Art

I have a recently purchased Oehler 35. It is not that easy to set up and transport, it comes with a Rifle case to carry it in. It is accurate, but I'm told it is not as state of the art as it should be. Oehler does sell an upscale system with transducers, it is not easy to get good info on. I also considered a Neco PVM NECO moly plating bullets,firelapping,QuickLOAD ballistic software and Kurzzeit precision chronographs . I could not get mush info on that either, but the design of the sensors looks solid. I usually use an Alpha Chrony, which packs up in a gunbag and offers me reliable although not 100% accurate FPS readings. But for sorting out a new load it gets the job done for me.

Thanks for the replies so quickly.

Here is one of the systems I was looking at:

RSI - PressureTrace

The problem I found was getting good info. Everyone purchases the cheaper models, I was unable to shoot over an Oehler before I bought it. I made my decision based on reviews and reputation, and waited 6 months on a list. The better systems definitely get scary expensive in a hurry, some of the tranducers only work with one cartridge. Some were priced without everthing needed to go to work.

Regarding putting a strain gauge on your firearm to measure pressure, I have some concerns.
First, are you merely curious, or is it your intent to use the pressure data from the equipment to load cartridges at pressure limits, even if it is more than published data?
If you intend to trust the pressure data to make max pressure loads, the strain gauge has to be installed just right, and then the firearm MUST be calibrated against lab equipment. Otherwise, you are risking damage and injury from lack of calibration, or calibration error. Strain gauges are very good at saying this one is more than that, but poor in giving absolute value.

I am a physicist with special work in sensors of many kinds, and am leary of consumer grade sensors, whether made for measuring the humidity or gun chamber pressures. It is easy to generate numbers, but whether they are sufficiently accurate is another matter.

__________________
Science plus Art

In 1977-1978 I had an Engineering 'Strength of Materials' lab course. One "experiment" involved a known lot of steel, strain gauge installation, and analysis of results. The results of 12 different student teams was frightening. At the low end the steel was slightly stronger than aluminum, at the high end the strength was greater than some of the new "Super Alloys" at that time. The steel had a yield strength of 37,000 psi and an ultimate tensile strength of 55,000 psi. Student results for yield strength varied from 14,000 to 120,000 psi.

The obvious lesson was that "application and installation" of a strain gauge is neither simple nor obvious. You are ultimately betting your personal safety on your "strain gauge technique" if you are testing for maximum safe loads in your rifle.

__________________
S&WHF 366

If you want new and different, check out the Magnetospeed. I bought one and so far it has been extremely reliable - very few missed shots. It's results are believable. In the near future I'll set it up with an optical chrono to compare results. Only negative so far, is there's no way to attach it to snubby or autoloader pistols. Longer barreled handguns, rifles, shotguns are just fine. There's no need to fiddle with skyscreen alignment and it's quite the conversation starter. Such as "Y'all got a bayonet on yer varmint gun?"

MagnetoSpeed

If you like the Oehler Model 33 so much I highly doubt you will be happy with any other company's Chrono. I have to add my vote to buying the Oehler Model 35P and enjoy another 30 years of use.

For me, I'm cheap. I bought a PACT and I'm very happy with it. All the guts are safe on the bench next to you while only the sensors are in harms way. It costs way less to replace the sensors when you shoot them instead of the whole Chrono... (don't ask!)

__________________
Freedom is never free!!
SWCA #3437

I don't need to ask. I have sent enough of those little black boxes to the Skyscreen Graveyard that when Oehler stopped making it I bought what should be a lifetime supply of replacement boxes and sensors.

It's not that I like the 33 so much, it's just that I have never felt like I needed more capability. Plug it in, turn it on, shoot and write down the numbers.

Now I wish I had all that data on the computer, and even more considering all the data I never wrote down that I would have had if the machine recorded it to a computer.

Oehler has always been the standard, but the newer units have nice features and the prices are right. I paid $300 for that 33 in 1985, $15 more than the .44 Blackhawk I bought the same year.

The intent would be to get accurate, and correct, pressure measurements. Several of the cartridges I load for do have applications in the area where pressure tested data is inconsistent or non-existant.

Load data may vary widely and in many cases no pressures are given, only a note that "this data does not exceed xxx psi" or "All loads are safe in Gun X, which can take pressures up to Y."

So yes, if I am going to spend the money for a pressure setup it must be accurate.

I thank you and Engineer1911 for your excellent comments and insight. Your professional qualifications in this area far exceed mine and I really appreciate the feedback.

It sounds like these consumer grade setups deliver results that may be considered relative to a known value. If I tested a load of known pressure against the system I could determine any deviation, but I would have to have the proven calibration load first. Not very likely, and without it is just guessing.

So how would you go about determining a maximum safe load without reliable pressure equipment?

The old ways of measuring case head expansion, rate of velocity increase relative to powder charge, extreme spread and standard deviation and primer signs are all very subjective, and in most cases amount to just guessing as well.

What do you think?

I used a PACT for about 20 years and like you, recently replaced it with a CED. At first I was skeptical it would produce similar velocities so I went about comparing them with the same shot over both screens. It turned out they were within 8 fps or less of each other so I have been using the CED exclusively and the PACT is now my shot timer.
A really nice feature of the CED is it's memory and USB download of all the data into Excel. Now I just record what string number the load is and maybe the average if I feel like it then Xref that string # when I get home. Makes range time so much faster.

Pretty neat system. It's very similar to how they used to measure velocity in large naval rifles and other long range artillery. Note the rings on the barrels.

b8b147502177LG.jpg Tirpitz Firing Web.jpg

On both Bismarck and Tirpitz it appears all the barrels were instrumented. I don't know if they left the devices on to continously feed velocity data to the gun directors or only used them to develop the firing tables. Now it's done with radar.

That would be cool, a miniature radar or laser to clock the outgoing bullet and it would be a worthwhile use for the accessory rails on all of today's guns.

The download to Excel is one of those features moving into the must-have column.

Are you using the Pressure Trace system?

I have limited experience with any chrono other than the Oehler 35P. In contrast to some other posts, I find it a joy to use. I get very consistent results within a session and can repeat the results months later. The sweet spot is large and the proof channel tells if the chrono didn't get a good reading. I have used it for about 15 years and I think the printer is the week link. I had to send my in for a replacement which cost about $50. I wouldn't want a chrono with the guts downrange. One errant shot and you get to buy a new chrono. I would agree that the Oehler is not as easy to set up when using a 4 foot spacing as I do. Maybe that forces one to shoot closer to the sweet spot.

__________________
Dick

IMO, you already have it in the 33. I have 35, always works, always gives reliable data. If you must have soemthing new, then the CED is about the best going on the market today IMO. This is based on me testing my 35 back to back to back w/ the CED & Chrony BM. All the Chrony line are just krap, really terrible screens. If I ever have to replace my 35, it will be the CED. I also have a PACT, also poor screens. Maybe the new screens are better, but my older PACT is also in the krap catagory.

__________________
NRA Cert. Inst. IDPA CSO

I have one as well and can second all of what was said above. Once I get it set up correctly I have had no missed shots.

However, on the down side the method of attachment changes the POI on all three rifles I've used it on. This makes it impractical to measure both accuracy and velocity on the same shots.

OTOH, it is extremely useful at indoor ranges or in other situations where setting up a chrono 10' down range is impractical. And its hard to put a bullet through it

That was the first thing that came to mind when I saw it, and I think the weight would also affect POI on handguns.

Still, it looks like it would solve certain common problems.

One issue I have when on the range using the skyscreens without diffusers is they will sometimes pick up my neighbors bullets and if I'm not payin attention it will ruin a string. Not a big deal, but one reason I prefer to chronograph on an empty range.

Well my old Oehler model 12 is still alive and kicking. Yea I occassionally miss a shot due to forgetting to hit the reset switch after rotating the dial to get the readings. It slows me down but helps with barrel cooling. I usually an shooting groups and/or working up a load for a new gun when I chronograph.

I wish I could afford a cool setup like that. I measure pressure the old fashioned way... finger to the wind.

another feature useful for crowd shooting is that you can delete or lock out a shot from your string in case you pickup someone else's blastwave. One button deletes it another merely removes it from the string calculation.