Magneto speed barrel mounted chronographs. Any experience?

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junkdude

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Anybody have any experience and comments regarding a magnetic chronograph?

h ttp://www.sinclairintl.com/shooting-accessories/range-measurement/chronographs/magneto-speed-barrel-mounted-chronographs-prod55606.aspx

This being a techno-toy, I'm thinking I might need one.
 
I used one for a few years - about 45 years ago. it is what we used in the CIL ammo R & D lab.

The advantage was that it would not be confused my muzzle gases, muzzle blast, wad columns, etc. It was also used to trigger a high speed strobe so we could take pictures of bullets and wad columns near the muzzle.

For the handloader, being independent of over head light quality would be an advantage.
 
There are some other Chrono threads on this board where people have talked a bit about them.
I suspect you could order direct instead of through Sinclairs but then again there doesnt seem to be any price markup between them http://www.magnetospeed.com/
Im kicking myself because it wasnt that long ago the company had some special introductory pricing which was quite a bit lower. I looked and thought nahhh ....and now I wish I would have purchased one. Have done some research on other boards where people have posted accuracy results and it seems to be very positive.
I might just wait until I take my next trip to the states and get one
 
Those are very interesting, I look forward to hearing a review or two. Their site is a bit light on the tech details, how can an electromagnetic sensor work with a lead bullet?


Mark
 
I've had one for a month or so. I've used it for a couple hundred rounds and it has been flawless. I get a slight change in point of impact - about 1" higher at 200 yards. I can't wait for better weather to compare it to my CED MII with IR and my buddy's new Oehler 35P.

The only drawback is the flimsy fastening strap with plastic buckle. Mine broke on the second outing. I now fasten the chrono to the barrel with electric tape!
 
mmattockx said:
Those are very interesting, I look forward to hearing a review or two. Their site is a bit light on the tech details, how can an electromagnetic sensor work with a lead bullet?


Mark
Click to expand...

only works with steel core ammo :)

i'm not 100% sure how it all works, but i suspect it's enough to mess with the magnetic feild as it passes by.
 
Spawn-Inc said:
only works with steel core ammo :)

i'm not 100% sure how it all works, but i suspect it's enough to mess with the magnetic feild as it passes by.
Click to expand...

from the realguns review (http://www.realguns.com/articles/360.htm) it does not work well with steel cored or lead bullets.
also it does not work with handguns (and I think shotguns are out of the picture too because usual shot is lead or steel).
pretty expensive for all it doesn't do
 
"Their site is a bit light on the tech details, how can an electromagnetic sensor work with a lead bullet?"

I spent hours in a lab range looking at a big set of coils plugged into an electronic unit the size of a small fridge (all vacuum tubes - remember those?) and all the time I was wondering how it could sense lead bullets and lead shot. But it did.
 
"Their site is a bit light on the tech details, how can an electromagnetic sensor work with a lead bullet?"
Click to expand...

I know the answer to that.
The unit generates an electromagnetic field and said field closes through the air. Whenever something passes through said air-space it slightly upsets the magnetic field. It's exactly how the MRI (magnetic resonance imaging) works. Out bodies are not ferrimagnetic and yet the unit detects minute differences in it's magnetic fields through out tissues.
The magneto-chrony seems not to be sensitive enough to detect the change when lead is involved.
Also the steel core may upset the fields for too long making the readings unreliable.
But it's all speculation.
 
legi0n said:
I know the answer to that.
The unit generates an electromagnetic field and said field closes through the air. Whenever something passes through said air-space it slightly upsets the magnetic field. It's exactly how the MRI (magnetic resonance imaging) works. Out bodies are not ferrimagnetic and yet the unit detects minute differences in it's magnetic fields through out tissues.
The magneto-chrony seems not to be sensitive enough to detect the change when lead is involved.
Also the steel core may upset the fields for too long making the readings unreliable.
But it's all speculation.
Click to expand...

Ah, ok. It is sensing the disturbance in the field, not the bullet itself. That makes more sense to me, thanks for the explanation. While the MS people claim it is no good with lead, the review posted seemed to work ok with lead bullets. Not working with handguns is a much bigger limitation for my purposes, I guess it will have to be a traditional chrony after all...


Mark
 
Not sure why it would not work with hand guns? The MS web site shows pictures of it on a handgun (all look like small caliber though). Possibly not semi's as no easy way to attach it.

It should work with any metal (maybe some better than others?), the material does not have to exibit magnetic properties to be a conductor of magnetic fields; same principle as magnetically dampened powder scales which use aluminum or copper to cut the magnetic field.
 
junkdude said:
Not sure why it would not work with hand guns? The MS web site shows pictures of it on a handgun (all look like small caliber though). Possibly not semi's as no easy way to attach it.

It should work with any metal (maybe some better than others?), the material does not have to exibit magnetic properties to be a conductor of magnetic fields; same principle as magnetically dampened powder scales which use aluminum or copper to cut the magnetic field.
Click to expand...

That is the problem, there is no reasonable way to attach it to a semi-auto that has the barrel enclosed by the slide (which is most of the handguns I own). Revolvers I can see being workable if there is enough barrel to mount the bracket to.


Mark
 
I've been using one for the past 2 months. I'm liking it more and more now that I've figured how to stop it from coming loose all the damn time. I've been using it solely for load development so far, so can't comment on the accuracy issue, although I haven't noticed a problem with grouping, that's for sure. The nice thing is I can set up multiple targets down range, and not worry about moving a chronograph, or shooting it (because I would be the guy to put a bullet through one from flinching). Last outing I took 40 shots with mine mounted and it never came loose, or gave any abnormal readings. I like that it's not affected by weather conditions (used it all the way into the dark one night testing different shotgun shells), muzzle blast, and I like having readings right at the muzzle vs. 10+ yards away. I feel the design is inherently more accurate than ones that rely on light, but I can't prove that. It also works just fine with my muzzle brake, in case some might be worried about that.

My only issues with it are that I can't use it on semi-auto handguns or my Savage 24v combo gun, and with heavy 3.5" 12 ga loads it slides back slowly, but hardly worth complaining about. I would suggest it, even though I don't have any experience with other chrono's. I haven't used steel-cored bullets yet, but there is a trigger setting for them built-in. I've had no problems with lead shot, copper/lead bullets or Barnes TSX bullets in getting readings, you can even adjust a custom trigger setting until you get accurate readings from whatever bullet you're using.

TT
 
legi0n said:
I know the answer to that.
The unit generates an electromagnetic field and said field closes through the air. Whenever something passes through said air-space it slightly upsets the magnetic field. It's exactly how the MRI (magnetic resonance imaging) works. Out bodies are not ferrimagnetic and yet the unit detects minute differences in it's magnetic fields through out tissues.
The magneto-chrony seems not to be sensitive enough to detect the change when lead is involved.
Also the steel core may upset the fields for too long making the readings unreliable.
But it's all speculation.
Click to expand...

It works because copper is conductive. Lead isn't sufficiently conductive to work, nor is steel. It's not about how magnetic the bullet is, but how conductive.

When you pass a magnetic field through a conductor (or vice versa in this case), it generates an electric current. To see this for yourself, drop a rare earth magnet through a copper pipe. You will be astounded. The magnet doesn't just drop through. It slows down substantially as it picks up speed. The magnet creates an electric field, which creates electro magnetism opposite to the movement of the magnet.
 
Interesting - it has many advantages over the traditonal chrony.

I suppose that gas-checked lead bullets would work better than plain-based.

I also suppose that with all the complaints about the attachment system, that the next version will improve upon that.
 
SandRoad said:
It works because copper is conductive. Lead isn't sufficiently conductive to work, nor is steel. It's not about how magnetic the bullet is, but how conductive.
Click to expand...

Not entirely correct. It is about magnetic permeability, unrelated to electrical conductivity. Lead and copper have a magnetic permeability almost the same as air, they are considered diamagnectic , the magnetic current tends to be less concentrated in these types of materials. Steel is ferromagnetic and concentrates the magnetic flux.

Magnet dropped through a copper pipe is slowed due to eddy currents causing drag, which slows the magnets fall. Same principle as magnetic dampened beam scale.

The chorongraph would have to be tuned to the type of material passing over the sensor, it needs to be looking for the correct type of disturbance of the magnetic field. Lead and copper would be problematic unless the sensor was correctly tuned... and if their chronograph didn't detect lead and copper I'd think they would be out of business fairly quick as not many shooters are interesting in a chrony that can't detect bullets. It is possible that typical metals alloyed with lead for bullets (tin, antimony, etc) change the magnetic properties of the alloy and make it easier to detect than pure lead.
 
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