Home Forums Hunting & Shooting Ask The Gunwriters Chronograph

Paired with the app on my phone I place my phone under the stock just in front of the trigger guard. Same place I position it when we're using electronic targets. You don't have to move out of position to manipulate the bottons on the LabRadar.

+1. I had the ProChrono Digital for probably around 20 years and served me well. Just upgraded to the DLX and bluetoothing velocities to my phone is great. Great buy IMO.

Prone shooting is quite easy with and Oehler system. Simply use a piece of PVC with a hole drilled in it and laid on the ground instead of the stands that come with the system. If shooting at extended distances, a simple wood triangle with holes drilled in it can be used to elevate the stop screen.

I use a triangle made of two pieces of wood with a couple of bolts and wingnuts to tighten. No holes to drill and infinite adjustment. I'll see if I can find a photo.

This is my setup for prone shooting.

I started with the Oehler M33 some 40 yrs back. It worked but was a pain to set up. My CED M2 lasted about a hot and messy minute. It would literally quit reading velocities during the late morning as the sun would reach a certain angle. CED replaced every piece of that unit, one piece at a time, over several months. The company president even called me while on a business trip to Hong Kong to verify I knew what I was doing. Love the Oehler M35p....except the set up time; especially on a public range day when the range has to be shut down to step out in front of the benches. LOVE LOVE LOVE my Labradar. Have yet to experience either item Mule Deer describes but then I don't shoot super fast nor super small bullets. I do use the external microphone for 22 LR.....and.....arrows....indoors to boot! Don't count on the Labradar indoors as their is too much radar wave scatter. The picture I'm posting shows the external microphone attached to the top of the rifle; I now simply set it on the bench surface under the barrel. In addition, if your range has closer target backers, such as the 25, 50 or 75 yd backers in the picture and you shoot over them to reach a longer range target backer, such as the 100 or 200 yd in the picture, the radar waves will, again, scatter, not picking up the shot. Oh, and a friend sold me the plastic aiming circle you see attached to the top of the unit. The little groove to use for aiming....bleeech!!!

Alan

I have an Oehler 35P which I have had for over 20 years. It originally was purchased sans printer, but added it later. I also bought the light kit to use it indoors, works very well.

Another satisfied user.

F-class john

and



dave

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For those having problems shooting skyscreens..


it dont get much simple than this .

35 dollar lazer from sightmark.
dave

I just put tape around the vertical bars about 5" up, align crosshairs, and call it good.

Yep, it's not "rocket surgery."

I shot holes in (3) shooting chronys in minutes
I shot holes in (2) pro chronos in minutes
I stopped shooting handguns over the 3rd pro chrono and it still works 15 years later.
I only shoot it over handguns after I verify I can hit the target.

I got a magnetospeed for $400 in 2015. I used it once. It is still on that 22. I don't like it.

I got a CEM M2 in 2019. I have not opened the box.

The pro chrono works too well to mess with the others.
It does have a problem a 2,500 feet elevation.
O2 and N2 scatter blue sunlight and make a background for the bullet to have a shadow.
There is not much O2 or N2 above me to make a shadow.
So I turn the pro chrono sideways and get a bullet shadow on a box.



No diffusors, no rods, at 2,500 feet.

Oct 4, 2014
1) I shot (5) rounds of 7mmRM 140 gr NBT 3.34" moly 70 gr H4350
through the Browning 1885. I had never shot the rifle. I just put
shims under front scope base and mounted Sightron SIII 3x10 scope
1) missed the target at 87 yards
2) bore sighted, and then 3.5 in high and 1 in to the left
3) Three shot group = 1/2"

3358 fps
3384 fps
3333 fps
3308 fps
3325 fps

Clark,

I think you’re misunderstanding the optical mechanism a little bit. While it’s true that the atmosphere scatters blue wavelengths more than other wavelengths in white light, which is why the sky “looks” blue, there is plenty of white light that reaches the Earth from the sun in a “line-of-sight” path.

My Pro Chrono works just fine at 5000 feet ASL, with or without diffusors.

That's a great idea...
Dave

John, I have read this before, and it does make sense. I do not mind POI shift, but I do like to shoot over a chronograph while working up loads. In your experience would you say the Magnetospeed will negatively affect group size? It seems to me if one is careful to not shift the unit on the barrel group size will be unaffected. Or does it mess so badly with the barrel harminics that it actually may? Would be interesting to knw if anybody has done a test with a "proven performer" in a particular rifle, then hung a Magnetospeed on the end and see if group size changes.

I may be confused, there is always the danger of hidden variables. And I know you are scary smart. But here in Seattle at 300 feet, the sky is a bright blue and the chrono triggers. In MT at 2500 feet, a clear sky [looking straight up] looks black and the chrono will not trigger. But with a little cloud cover at the same spot at 2500 feet, it will trigger.

I can think of a hidden variable. Your chrono could have a trigger set to a more sensitive threshold than mine.

I wish I was smart enough to have come up with it. Dr. Oehler is the one that I got it from.

I have seen a Magnetospeed mounted on the barrel affect group size many times, sometimes drastically. It affects lighter-weight barrels more, but have seen it happen in barrels as large as .7 inch at the muzzle.

I have and yes it does. I find my accuracy first then velocity.

They have gotten me out of a jamb or two over the phone as well.
My model 33 that I bought in 1986 is still keeping on.
I use it more now than ever.
Fresh set of batteries. And I'm GTG for another year.

Dave

I don't doubt your experiences, and it is true that at lower elevations there is more atmospheric scattering causing a greater amount of anisotropic blue light, but there is also a lower intensity of direct, isotropic white sunlight reaching the ground exactly because there is less atmosphere scattering the incoming light.

You're right that the sensitivity of the sensors in my ProChrono unit may differ from the sensitivity of the sensors in your unit. It would be interesting to know what type of light sensors the ProChrono uses, as the sensitivity of different optical sensors to various wavelengths of light varies. It may well be that the sensors that the ProChrono uses are most sensitive to blue wavelengths, in which case they would work well at high elevation where the incident angle of white sunlight causes sufficient shadow when the bullet passes by, but poorly where angle of the sun is such that the shadow is mainly caused by scattered atmospheric blue light. It makes sense that your unit triggers at higher elevation under cloud cover, as the clouds act as a diffuser increasing the anisotropy of the white light.