What is the best electronic target

[7mm]

Looking into pairing a downrange electronic target with the chrono into my load development, what are some of the best options and why?

 

[Maurygold]

shotmarker end of story

 

[CoryT]

shotmarker end of story

This ^^^

I use three of these for the XLR class, there are no subsitutes.

 

[smoothy8500]

The other option is the Solo/Silver Mountain, but Shotmarker is still better. We use both in our matches and we have found they are both very accurate and have ability to give velocity and SD’s at the target.

However, the wires and connections on the Solo/silver mountain transmitter and antenna are very fragile. We are constantly replacing these cables and connecting plugs.

 

[7mm]

How does one go about determining BC from using a shotmarker?

 

[Maurygold]

How does one go about determining BC from using a shotmarker?

Difference in speed from muzzle to target

 

[7mm]

Difference in speed from muzzle to target

Yeah I get that part, but then what? Is there a formula or specific ballistic calculator that simplifies the process? Or do I just keep modifying the inputs until the BC matches?

 

[7mm]

This ^^^

I use three of these for the XLR class, there are no subsitutes.

XLR class?

 

[smoothy8500]

XLR class?

IDK, maybe trying to be PC and use the abreviation to keep things on the DL and prevent people from being all "WTF?"...

 

[Maurygold]

Yeah I get that part, but then what? Is there a formula or specific ballistic calculator that simplifies the process? Or do I just keep modifying the inputs until the BC matches?

If you’re using a well known ballistic solver you can true the bc based on the actual velocities.

 

[Rio Precision Gunworks]

How does one go about determining BC from using a shotmarker?

Approach using Shot Marker velocities with caution. It requires very diligent setup of the sensors. Also, even the manufacturer advises caution when using the chrono numbers.

Systems like an Oehler 89 utilizes time of flight and the velocity at the muzzle. Which is going to be a much better way than using velocity readings downrange. It's much easier for sensors/microphones to pick up that a bullet passed by the sensor than it is to get an accurate velocity.

Obviously bullets with a higher BC will get to the target faster and thus will have higher velocity at the target. But it's the collection of the data that requires meticulous setup vs something measuring TOF.

 

[CoryT]

I speak of the Extreme Long Range (XLR) class here at Gunsite. Yes, the target setup need to be precise, Mine are built on Aluminum frames with the mounts drilled on a milling machine, laser measured center-to-center. I've tested mine against a Labradar in Doppler mode downrange and they are +/- 3fps, so that seems to work for ballistic software calibration, The 89 would be great, but far more expensive and harder to setup. Really I'd like a full-size radar system, but 100K is not in my budget, even after pulling the loose change from the couch cushions.

 

[7mm]

What is the best option then for truing bc's for around the price of the shotmarker? $3000 for the oehler is a little more than I want to spend and the set up is quite intensive.

 

[Maurygold]

What is the best option then for truing bc's for around the price of the shotmarker? $3000 for the oehler is a little more than I want to spend and the set up is quite intensive.

That is the shotmarker. kestrel should have a cdm that’s close to whatever you shoot at that point your extremely close if not exactly on bc

 

[CoryT]

There is nothing better. Make a sturdy, non-flexible frame, with precision measurements for the sensors. Calibrate it against your chrongraph. Between the velocities and precision of the group placement, truing is easy.

 

[7mm]

Sounds good, looks like I know what I'm getting myself for Christmas haha.

That is the shotmarker. kestrel should have a cdm that’s close to whatever you shoot at that point your extremely close if not exactly on bc

Can you expand on the custom drag model aspect?

 

[Maurygold]

Sounds good, looks like I know what I'm getting myself for Christmas haha.

Can you expand on the custom drag model aspect?

yeah kestrel has custom drag models they created for shooters who used their doppler. if you're using a popular bullet (you should be shooting Berger) someone has likely shot it close to the speed you are and those two things will give you an extremely close BC

 

[7mm]

yeah kestrel has custom drag models they created for shooters who used their doppler. if you're using a popular bullet (you should be shooting Berger) someone has likely shot it close to the speed you are and those two things will give you an extremely close BC

I am shooting burgers but I also shoot custom bullets than dont have published bc, thats really the reason I'm going down this road.

 

[Maurygold]

I am shooting burgers but I also shoot custom bullets than dont have published bc, thats really the reason I'm going down this road.

Id be surprised if the manufacturer of any custom monos or small batch lathes doesn’t have that data.

 

[7mm]

Id be surprised if the manufacturer of any custom monos or small batch lathes doesn’t have that data.

Its not a mono or lathe spun.
They are swagged and jacketed RBT's
I do have an estimated bc but I want real world numbers.