Range Report new chron technology...

[cali_tz]

apologize if this has been posted elsewhere... has anyone tried this new magnetospeed chron? Looks quite accurate and uses non optical methods to measure speed, which implies increased accuracy. More expensive than my CED, but if it actually works all the time, that would be worth the cost. My CED is finicky with respect to light conditions. This new product could care less, but it does require copper jacketed rounds, and it cannot mount on handguns... just rifles, and those without a can mounted.

http://www.magnetospeed.com/index.html

 

[azimutha]

Re: new chron technology...

Looks decent and if it works like they claim would sure beat a read chrony and tripod. I've considered the CED but have heard enough complaints to wonder if it would improve on what I have.

 

[cali_tz]

Re: new chron technology...

I sent them an email with an inquiry, but haven't heard back yet. We'll see if they are for real.

 

[Cegorach]

Re: new chron technology...

Being mounted on the barrel it would force you to do you to look at the accuracy and velocity aspects of your load development separately. Not ideal if you ask me.

 

[High Binder]

Re: new chron technology...

$250! They've gotta do a lot better than that especially with it's limitations.

 

[Lowlight]

Re: new chron technology...

Terry Cross is mentioned on their site, so maybe he can shed some light on it.

Always interested in something new, I wonder if you can actually mount it on a suppressor if it had a TAB Cover on it ? Another question though would be muzzle brakes, how would that effect it ?

 

[taliv]

Re: new chron technology...

i've been in email discussion about suppressor compatibility. it appears possible if you mount the sensor externally. however, you've got to get REALLY close to the bullet

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">i would try to get the bullet well within 0.3" of the sensor deck and as parallel as possible. a 50 cal round coming out of your 1.5" suppressor would stand about 0.56" away from our sensor deck (normally mounted). we've tested extensively (and extremely successfully!) with a bbl 300 winmag. it has a 0.88" diameter muzzle so the wall thickness is about 0.29". our unit's sensor deck sits only about 40-60 thousandths lower than the barrel edge (depending on how the diameter sits in the vee-block), so our standoff (sensor to bullet edge) is about 0.34" in that situation.</div></div>

 

[cali_tz]

Re: new chron technology...

I asked them about muzzle brakes and they said it should not be a problem, but at this point they need to see a picture of the barrel/break before they can predict compatibility.

The point about accuracy vs speed is not relevant for me, while it could be very relevant for others. The reason is I have such trouble getting good data with the CED device, that to also try and line up the CED with a large enough target for tuning barrel harmonics is too difficult. I rather get to my target speed, and then see if there is a harmonics problem. For my shooting needs, getting MV accurately and tightly grouped (in speed) is more important at this time.

 

[Fred_C_Dobbs]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">...uses non optical methods to measure speed, which implies increased accuracy....</div></div>
Why? Chronograph accuracy is a function of the frequency of the timing circuitry, not the detection method.

Precision is a function of the detection method but since nothing travels faster than light, there is nothing than can provide any more instantaneous a start and stop signal to the timing circuit.

 

[azimutha]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fred_C_Dobbs</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">...uses non optical methods to measure speed, which implies increased accuracy....</div></div>
Why? Chronograph accuracy is a function of the frequency of the timing circuitry, not the detection method.

Precision is a function of the detection method but since nothing travels faster than light, there is nothing than can provide any more instantaneous a start and stop signal to the timing circuit. </div></div>

I would think it's less susceptible to problems that sometimes plague optical systems like too much reflected light (off snow, for instance), sun angle or debris. So in practical use it may be more accurate. Ideally, we'd all be able to afford Doppler radar systems. AFAIK they don't use the speed of light either.

As for not being able to test both accuracy and velocity simultaneously, I doubt the unit weighs that much. Even if it does impact accuracy, for people like me who don't change loads very often or don't shoot with a can some of the time, it wouldn't be an issue. If I need to test MV, I run 10 rounds and call it good...maybe do it another time when it's 0F vs. 100F just to see how much variation I can expect. (All powders, even Varget, will lose or gain some, although I've only seen about 20-25 FPS variation* on either side of my normal range temps of 45-60F).

*I should add this is with a chrony I don't entirely trust. It needs a new battery to work at all and in the cold and with nearby snow, I had to wonder if it wasn't jerking me around.

 

[gstaylorg]

Re: new chron technology...

I am pretty tired of the time it takes to set up/adjust/take down my chronograph and tripod when the range is cold, particularly with the severely limited range hours where I currently shoot.

For this reason alone, if this device does what it's advertised to do, it will be worth every penny IMO. After reading this thread yesterday and looking over the info on their site, I added my name to the "buy" list. So whenever they become available, I'll post a review if someone else hasn't already.

 

[memilanuk]

Re: new chron technology...

I'm at about the same point... I have a CED Millenium and while it works pretty well most of the time, I get tired of having to screw around setting it up when other shooters are at the range - including answering the same stupid questions every time. Something like this where I could chrono a string without ever having to go forward of the firing line would be very nice... though I can just heard the assinine comments about 'fix bayonets!'...

 

[cali_tz]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fred_C_Dobbs</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">...uses non optical methods to measure speed, which implies increased accuracy....</div></div>
Why? Chronograph accuracy is a function of the frequency of the timing circuitry, not the detection method.

Precision is a function of the detection method but since nothing travels faster than light, there is nothing than can provide any more instantaneous a start and stop signal to the timing circuit. </div></div>

Magnetic field changes travel the same speed as the speed of light, since light is nothing but electromagnetic field wave. The problem I see with the optical chron method is that to work best it requires a diffuse light source directly overhead. While the magnetic method could very directly compare a peak of a magnetic field on one end, to the the same magnetic peak on the farther end of the detector and get even better same point to same point detection of bullet passing overhead, AND without any of the requirements of light angle and quantity.

So detection method is a factor, as well as timing. Garbage in, garbage out.

 

[zipollini]

Re: new chron technology...

Funny that I should just happen onto this site below just yesterday

http://www.airrifleshop.co.uk/Accessories/Chronograph.htm

 

[cali_tz]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: zipollini</div><div class="ubbcode-body">Funny that I should just happen onto this site below just yesterday

http://www.airrifleshop.co.uk/Accessories/Chronograph.htm </div></div>

no real description of how it works... wonder if it's designed for airsoft and nothing else?

 

[Fred_C_Dobbs]

Re: new chron technology...

There are some tricks to reducing your CED set-up time, like marking the diffuser supports with the correct heights over the sensors, using a laser bore sighter to be certain you're positioning the chrono correctly without having to run back and peek through the scope, and putting a magnet on a 10-foot (or 12 or whatever) piece of string to consistently get the chrono a known distance from the muzzle. I also carry a 3-foot long piece of 3/4" pvc tubing in case I arrive while the range is cold and I can't uncase my rifle. I put the tube on the sandbags and train it on the bulls-eye as a stand-in for the rifle, remembering that the tube is sighting a couple of inches lower than the scope itself will.

It'll cure 99% of the lighting problems with a CED if you add the IR lighting. But that makes it even more time-consuming to set up.

They might cost more than an Oehler 35P but I think the Kurzzeit PVM-08/21 is the ideal solution because it's stupid-simple to set up and only comes with built-in IR.

 

[cali_tz]

Re: new chron technology...

$750 for the Kurzeit puts it out of my budget for this piece of eqpt. Do you still have to line it up all special like the CED or is the zone of detection much wider...?

 

[cali_tz]

Re: new chron technology...

btw on the topic of a chron like this messing with barrel harmonics... what does screwing on a can do to a rifle platform... it also clearly affects harmonics putting this weight on the very end of the whip...?

 

[mouse07410]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">btw on the topic of a chron like this messing with barrel harmonics... what does screwing on a can do to a rifle platform... it also clearly affects harmonics putting this weight on the very end of the whip...?</div></div>
Certainly it does - which is why your "canned" zero differs from one without a can (and your brake'd zero is likely to differ from both).

The inconvenience I see - I usually zero my rifle and chronograph my ammo at the same time. It would be 100% useless for me to know a "chronograph zero".

 

[Leaddog]

Re: new chron technology...

I'd like something less cumbersome than my Oehler 35, but I have no complaints as to it's accuracy. Nothing worse than shutting down a busy firing line while I fiddle with the screen set-up though.

With this age of technology, I suspect we'll see many new offerings. That will be a good thing.

 

[cali_tz]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mouse07410</div><div class="ubbcode-body">
The inconvenience I see - I usually zero my rifle and chronograph my ammo at the same time. It would be 100% useless for me to know a "chronograph zero".

</div></div>

agreed. But it would be useful to measure my MV's more often, because I don't have the obstacle of setting up the traditional chron. If you have time and you are at a private range where you can tweak everything so you can chron and zero the rifle with each shot, that's great. I'd like to do so as well. I don't like wasting ten rounds down range just to confirm MV.
If I have to waste ten rounds, I'd like to measure zero at the same time.

So I guess this chron approach doesn't really work well for me either.

 

[gstaylorg]

Re: new chron technology...

Until someone tests one and reports back, it's completely unclear <span style="font-style: italic">how much</span> this device might change POI @ 100 yd. Using the suppressor example from above, it might be only a very small amount, it might be a lot. As a guess, it will probably also depend quite a bit on the specific rifle/barrel combo on which it's mounted. Personally, it will be worth sacrificing 10 rounds to me if it gives decent MV data, regardless of what happens to POI. Having (stupidly) put rounds through a shooting Chrony twice in the past few years, the cost of 10 rounds would be well worth the hassle involved setting up and using (or replacing LOL) a Chrony or similar device at a public range. JMO.

 

[Fred_C_Dobbs]

Re: new chron technology...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">btw on the topic of a chron like this messing with barrel harmonics... what does screwing on a can do to a rifle platform... it also clearly affects harmonics putting this weight on the very end of the whip...?</div></div>
This was posted by Chris Long, father of the Optimum Barrel Time load development method, in another forum in response to essentially the same question:

"I have found that muzzle brakes do not affect the minimum group size charge weight like you would think. They definitely affect the Point Of Impact (POI) as they completely change the bending mode vibration periods of the barrel system. I also know that the shock wave does not couple well, if at all, through a simple threaded joint. The extra material is not part of the shock wave system for the most part. In other words, the brake (or suppressor, in your case) does not change the shock wave timing as the effective length is still between the bolt face and the muzzle crown (behind most of the suppressor). I have experimented with my braked rifles, and find the minimum group charge weight does not change with and without the brake. However, that is not to say that the group sizes or group POIs are identical between the two conditions. Just that the group size minimum is still where the OBT velocity predicts."

 

[azimutha]

Re: new chron technology...

So really what's needed is a sensor pair mounted on a longer mount that attaches to the stock or a picatinny rail. For example, I have SRS rails underneath my stocks for my bipods. In other words, a mount that is independent of the barrel. I don't know if it could be done, but ideally the sensors could be mounted an inch or more from the muzzle. But I will have to consult my beer further to figure out how to counteract muzzle blast.

 

[mouse07410]

Re: new chron technology...

@azimutha, yes - if this device can be made to work with rifle calibers (like 338LM) then mounting it on a Picatinny rail should be no-brainer, including the ability to accommodate for the distance between the rail end and the muzzle.

Let's see how they develop it?

 

[cali_tz]

Re: new chron technology...

yes these are good ideas... that would make this a real winner product. somebody should contact them with this feedback.