Magnetospeed Barrel Mounted Chronograph

I have most certainly used these and am in no hurry to go back to the old kind. I have used the barrel mounted ones at night time, bright sunshine and in the rain with good testing results.
I only use it to check speeds and don't really get to shoot groups with it, but some say it does affect the zeros and tune, some say it doesn't.
 
The Magnetospeed is just so handy. Basically, keep it with you all the time and when you want to capture velocity, put it on. No fuss, no muss, no cease fire. Not affected by light conditions, target angle, etc. Very consistent.

Oh, and you can shoot good groups with one on the barrel.

 
I'm only looking for a convenient way to check velocity. This looks like a winning tool. Thanks. :)
 
I'm emotionally with Francis on this. It's logical on so many fronts. I just wished that I hadn't watched a friend shoot F class with it at 1000 yards with no change to his elevation zero when it was on or off.
 
In favour with Magnetospeed

I bought a magnetospeed unit about a year ago. One of the first things I did was check the calibration with a signal pulse generator. Very accurate between 1500fps and 3800fps. Showed about 6% faster when the velocity was under 1500fps and about the same slow reading over 3800fps. Nor was it influenced by lighting, target angle etc. Sold my Oehler and don't miss it.

As far as grouping with it attached to the barrel. Forget it. The BR rifle essentially doubled its group size with it attached. The field rifles which don't shoot as well as the BR rifle did worse.But I don't care. If I am checking velocities I am not trying to shoot tight groups and vice versa
Andy.
 
HuskerP7M8 said:
Hi Andy,

After checking the accuracy of the unit, did you also try measuring the precision?

Thanks,
Landy
Click to expand...

I think what you are really asking is whether the shot to shot or in this case pulse to pulse variation varied very much. A couple of feet per second which is about what I would expect with the type of circuits being used. The circuits are not thermally shielded either so these variations could increase and decrease between hot and cold days. Nor did I check it to see how vulnerable it was to interference from such things as mobile phones etc. But for all intents and purposes it is ahead in many respects for convenience and accuracy compared to anything they have come up with in the past.
Andy.
 
As a side note...

From a dog lover, I hope this fellow doesn't shoot too many center fire rounds with his dog standing near. Good way to make the pooch deaf prematurely. I wonder if there is a life span to the barrel mounted sensor given the intensity of the muzzle blast of a centerfire? Good video and interesting product.
 
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Purchased the V1 yesterday. They don't seem to be discounted, however I found one at Midway USA for $265. Ten dollars less than the retail price of $275, plus Midway gave me a September discount [till the 25th] of $20. $245 total. Magnetospeed's HQ, incidentally, is here in Austin.
 
Andy Cross said:
I bought a magnetospeed unit about a year ago. One of the first things I did was check the calibration with a signal pulse generator. Very accurate between 1500fps and 3800fps. Showed about 6% faster when the velocity was under 1500fps and about the same slow reading over 3800fps. Nor was it influenced by lighting, target angle etc. Sold my Oehler and don't miss it.

As far as grouping with it attached to the barrel. Forget it. The BR rifle essentially doubled its group size with it attached. The field rifles which don't shoot as well as the BR rifle did worse.But I don't care. If I am checking velocities I am not trying to shoot tight groups and vice versa
Andy.
Click to expand...

I have used my MagnetoSpeed numerous times at 600yd with my 6BR and the group sizes have been close to or the same with or without the MagnetoSpeed installed. The POI, point of impact of the group does change but corrections to the scope elevation and windage can correct the group POI.

I am adding to this post the results of a comparison I did several months ago with and without my MagnetoSpeed installed on my 6mm BR/30" barrel. I tested at 600 yds with calm to light right to left crosswinds and some light mirage. All in all the conditions were pretty good. When I returned home I measured the target/groups on my computer using the On Target Precision Calculator Target 2.1 Program. The first 4 shot group without the MagnetoSpeed measured 1.346" wide x .540" tall and the second 4 shot group with the MagnetoSpeed installed measured 1.390" wide x .506" tall. The group with the MagnetoSpeed was 4.281" down and 1.291" left center to center from the group without it. When I shot the second group the right to left crosswind was slightly increasing. I made no sighting corrections for the winds when I shot these groups. When I have done test like this before just resetting the scope will usually correct the group displacement. The group to group displacement also seems to vary according to caliber and loads and also will be smaller at shorter distances. Like I said this test was done at 600yds.
 
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HuskerP7M8 said:
Hi Andy,

After checking the accuracy of the unit, did you also try measuring the precision?

Thanks,
Landy
Click to expand...
I'm sure that the 6" spacing between the detectors comes into play here. As would the sensor excitation frequency.
 
I can't explain that

Texas Plinker said:
I have used my MagnetoSpeed numerous times at 600yd with my 6BR and the group sizes have been close to or the same with or without the MagnetoSpeed installed. The POI, point of impact of the group does change but corrections to the scope elevation and windage can correct the group POI.

I am adding to this post the results of a comparison I did several months ago with and without my MagnetoSpeed installed on my 6mm BR/30" barrel. I tested at 600 yds with calm to light right to left crosswinds and some light mirage. All in all the conditions were pretty good. When I returned home I measured the target/groups on my computer using the On Target Precision Calculator Target 2.1 Program. The first 4 shot group without the MagnetoSpeed measured 1.346" wide x .540" tall and the second 4 shot group with the MagnetoSpeed installed measured 1.390" wide x .506" tall. The group with the MagnetoSpeed was 4.281" down and 1.291" left center to center from the group without it. When I shot the second group the right to left crosswind was slightly increasing. I made no sighting corrections for the winds when I shot these groups. When I have done test like this before just resetting the scope will usually correct the group displacement. The group to group displacement also seems to vary according to caliber and loads and also will be smaller at shorter distances. Like I said this test was done at 600yds.
Click to expand...

It seems odd that something loosely attached to the end of the barrel has no effect on the grouping ability. Virtually every short range BR rifle I saw shoot with one attached essentially doubled the group size at 100 and 200 yards. Not that it really matters as no one tries to shoot tight groups while checking velocities. You are either doing one or the other.
Andy.
 
Constants

Vibe said:
I'm sure that the 6" spacing between the detectors comes into play here. As would the sensor excitation frequency.
Click to expand...

Yep the six inch spacing would have been chosen by the designer for a reason. I doubt if they tossed a coin to determine that. But it is a constant. The spacing doesn't vary. The gauss of the magnetic field - which is also a constant - would have been selected for the excitation band widths and amplitudes it would respond to as well as the material the bullet is made from.
Andy.
 
Andy Cross said:
It seems odd that something loosely attached to the end of the barrel has no effect on the grouping ability. Virtually every short range BR rifle I saw shoot with one attached essentially doubled the group size at 100 and 200 yards. Not that it really matters as no one tries to shoot tight groups while checking velocities. You are either doing one or the other.
Andy.
Click to expand...

Your statement about "something loosely attached to the end of the barrel" makes me wonder if you were installing the bayonet correctly. The instruction manual says to pull the cinch strap up through the strap adjuster until ALL the slack is taken up around the barrel. Then tighten the Thumb Nut against the Screw Frame until tight. Test the grip of the strap by tugging on the bayonet; if it is unmovable then proceed. If not, continue tightening the Thumb Screw. I know that when I follow the installation instructions my bayonet is extremely tight and unmovable and not "loosely attached to the end of the barrel" as you indicated. If it is "loosely attached" it probably will affect your grouping.

The figures that I gave you are what they are and I have repeated similar groups several times. I know other shooters that have had similar experiences as I have had with the Magetospeed and although I have not, there are some who have shot in competition with it installed.
 
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Andy Cross said:
I think what you are really asking is whether the shot to shot or in this case pulse to pulse variation varied very much. A couple of feet per second which is about what I would expect with the type of circuits being used. The circuits are not thermally shielded either so these variations could increase and decrease between hot and cold days. Nor did I check it to see how vulnerable it was to interference from such things as mobile phones etc. But for all intents and purposes it is ahead in many respects for convenience and accuracy compared to anything they have come up with in the past.
Andy.
Click to expand...

Andy,

Thanks and also sorry. My question wasn't concise enough and you had to assume what I was inquiring about.
Here's where I'm coming from and it's probably more info than anyone wants to hear about. LOL

Some time ago (7 or 8 years?), I decided to build a testing facility with tunnel and I wanted to incorporate a dual chronograph system capable of "accurately" measuring MV and "precise" enough to gather ballistic data for calculation of drag coefficients when one of the units was positioned downrange. I wanted to use a chronograph system in conjunction with some very sophisticated analytical software written by an experimental physicist I've worked with for quite some time and a semi-automatic electronic targeting system that would allow me to capture the x,y coordinates on a Cartesian Plane for every single shot I fired.

Anyway, to make a very very long story much shorter, I wrote several lengthy posts on another forum detailing everything I'd done over about a two year period to measure accuracy, precision, and calibrate the two chronographs. It generated a lot of feedback, PM's, and inquiries thru email asking my opinion on various chronograph systems.
In several of those inquiries about the MagnetoSpeed I expressed my concern that the MagnetoSpeed chronograph's sensor distance (as Vibe pointed out) was one of my major concerns, as was the clock speed.

I "think" you've answered my question regarding accuracy and the degree of precision appears to satisfy the demands of most, for a very convenient and very practical method of gathering velocity data. I still have a lot of questions concerning the precision of the unit, but of the dozen or so shooters I've visited with....all seem to be satisfied with the MagnetoSpeed.

Thanks,
Landy
 
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Define tight

Texas Plinker said:
Your statement about "something loosely attached to the end of the barrel" makes me wonder if you were installing the bayonet correctly. The instruction manual says to pull the cinch strap up through the strap adjuster until ALL the slack is taken up around the barrel. Then tighten the Thumb Nut against the Screw Frame until tight. Test the grip of the strap by tugging on the bayonet; if it is unmovable then proceed. If not, continue tightening the Thumb Screw. I know that when I follow the installation instructions my bayonet is extremely tight and unmovable and not "loosely attached to the end of the barrel" as you indicated. If it is "loosely attached" it probably will affect your grouping.

The figures that I gave you are what they are and I have repeated similar groups several times. I know other shooters that have had similar experiences as I have had with the Magetospeed and although I have not, there are some who have shot in competition with it installed.
Click to expand...

You mention cinch strap and thumbscrew. Those terms are contradictory to making an attachment tight and unmovable. Just touch the end of the bayonet lightly with a finger. You can see it move. Which in my opinion is loose. I couldn't get the system any tighter. But as I mentioned it doesn't matter as it won't be shot with it attached anyway.
Andy.
 
When it really matters

HuskerP7M8 said:
Andy,

Thanks and also sorry. My question wasn't concise enough and you had to assume what I was inquiring about.
Here's where I'm coming from and it's probably more info than anyone wants to hear about. LOL

Some time ago (7 or 8 years?), I decided to build a testing facility with tunnel and I wanted to incorporate a dual chronograph system capable of "accurately" measuring MV and "precise" enough to gather ballistic data for calculation of drag coefficients when one of the units was positioned downrange. I wanted to use a chronograph system in conjunction with some very sophisticated analytical software written by an experimental physicist I've worked with for quite some time and a semi-automatic electronic targeting system that would allow me to capture the x,y coordinates on a Cartesian Plane for every single shot I fired.

Anyway, to make a very very long story much shorter, I wrote several lengthy posts on another forum detailing everything I'd done over about a two year period to measure accuracy, precision, and calibrate the two chronographs. It generated a lot of feedback, PM's, and inquiries thru email asking my opinion on various chronograph systems.
In several of those inquiries about the MagnetoSpeed I expressed my concern that the MagnetoSpeed chronograph's sensor distance (as Vibe pointed out) was one of my major concerns, as was the clock speed.

I "think" you've answered my question regarding accuracy and the degree of precision appears to satisfy the demands of most, for a very convenient and very practical method of gathering velocity data. I still have a lot of questions concerning the precision of the unit, but of the dozen or so shooters I've visited with....all seem to be satisfied with the MagnetoSpeed.

Thanks,
Landy
Click to expand...

When you really have to know what speed an object is travelling at, its rate of acceleration, deceleration, energy losses etc then you have to spend some serious money on systems using broad beam tracking lasers and the like, connected to computers with insane clock speeds. Spending 300K would not be out of the question. But for most of us the consistency produced by the magneto type chrono's should be adequate.
Andy.
 
:D
Andy Cross said:
You mention cinch strap and thumbscrew. Those terms are contradictory to making an attachment tight and unmovable. Just touch the end of the bayonet lightly with a finger. You can see it move. Which in my opinion is loose. I couldn't get the system any tighter. But as I mentioned it doesn't matter as it won't be shot with it attached anyway.
Andy.
Click to expand...

Cinch strap and thumbscrew are the terms used by the MagnetoSpeed manufacture in their instruction manual. If you think those terms are contradictory to making an attachment tight and unmovable as they state then maybe you should do all us MagnetoSpeed owners a favor and ask them to correct those terms in their manual.

Then above you said "it won't be shot with it attached anyway" so how will you make it work, hold it in front of the barrel. Just joking.
 
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I don't believe

Texas Plinker said:
Cinch strap and thumbscrew are the terms used by the MagnetoSpeed manufacture in their instruction manual. If you think those terms are contradictory to making an attachment tight and unmovable as they state then maybe you should do all us MagnetoSpeed owners a favor and ask them to correct those terms in their manual.

Then above you said "it won't be shot with it attached anyway" so how will you make it work, hold it in front of the barrel.
Click to expand...

I don't believe that magnetospeed had any intentions of making the unit attache tightly enough so that it was considered unmovable. Just tight enough to keep it in place when subjected to muzzle blast and recoil. But when you think about it that's all that's needed isn't it.

Let me clarify the last bit for you. It won't be shot attached to the barrel at any other time other than when you are checking the velocities. Well I wouldn't imagine any shooter thinking otherwise. Would you ? So yes of course I will attache it to the barrel when using it. Hold it up in front of it give me a break.
Andy.
 
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