There would probably be a large following for our results. We might have to do that some time.
- Thread starter wyosniper
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There would probably be a large following for our results. We might have to do that some time.
When you have two clocks showing two different times, how do you know which ones right
That's easy. There is little doubt that the Oehler is accurate, it's just a PITA to set up, carry, store, etc. The Magnetospeed is a compromise for convenience. It would be a very big plus for the Magnetospeed if it could be shown to be both convenient AND accurate.
Let us know your results! As mentioned earlier, I do not think the magnetospeed is a compromise in accuracy and for all we know can be more accurate.
I think someone did a test between the two already (over at longrangehunting) and the oehler and magneto speed where right in line with each other (with the magneto speed reading slightly faster since its closer to muzzle). So that most likely answers that question!
Because the MagnetoSpeed's sensors are ALWAYS the same distance apart, there are no errors due to distance-between-sensors varying from setup to setup. However, since all clocks in these types of devices have some kind of error/variability, given the *SAME* clocks Magnetospeed's short distance would lead to larger variations, to the extent there are any.
Frankly, I don't think any of that matters, as long as you don't adjust the sensors on an optical chrono in between shots. Today your optical chrono's setup might yield "2800" when yesterday given the *SAME* bullet it might have said "2799" . . . pffft. All of today's bullets will be measured in the same way, and that's what matters most.
Whenever you can shoot without worrying about where the bullets hit (within reason, of course) and have a barrel to attach it to, the MagnetoSpeed is the superior device. Virtually no setup, is always the same distance from the barrel, gives true muzzle velocity, can be used rain or shine, light or dark, or any combination thereof.
Unfortunately, that limits the MagnetoSpeed's utility significantly. When I want to (eg) OCW, I need to make 3 extra bullets for each weight, fire them, and even then I do not know what the FPS was for the rounds actually used in OCW.
As said above, the ideal is to have both types . . . and so I have a CED M2 and a MagnetoSpeed lol.
Frankly, I don't think any of that matters, as long as you don't adjust the sensors on an optical chrono in between shots. Today your optical chrono's setup might yield "2800" when yesterday given the *SAME* bullet it might have said "2799" . . . pffft. All of today's bullets will be measured in the same way, and that's what matters most.
Whenever you can shoot without worrying about where the bullets hit (within reason, of course) and have a barrel to attach it to, the MagnetoSpeed is the superior device. Virtually no setup, is always the same distance from the barrel, gives true muzzle velocity, can be used rain or shine, light or dark, or any combination thereof.
Unfortunately, that limits the MagnetoSpeed's utility significantly. When I want to (eg) OCW, I need to make 3 extra bullets for each weight, fire them, and even then I do not know what the FPS was for the rounds actually used in OCW.
As said above, the ideal is to have both types . . . and so I have a CED M2 and a MagnetoSpeed lol.
All of the above is excellent advice, but how you shoot your groups can have an effect on your numbers.
I warm up the barrel by shooting 2 fouling shots one minute apart, leaving the bolt open between shots, then I go for the numbers also letting the barrel cool between shots. I also try not to leave the cartridge in a hot chamber any longer than necessary.
Time consuming and hard to do with semi auto, but it has helped the numbers tighten up some for me.
I warm up the barrel by shooting 2 fouling shots one minute apart, leaving the bolt open between shots, then I go for the numbers also letting the barrel cool between shots. I also try not to leave the cartridge in a hot chamber any longer than necessary.
Time consuming and hard to do with semi auto, but it has helped the numbers tighten up some for me.
I have both the Oehler and MagnetoSpeed. I shoot at an indoor range and an outdoor range with a cell tower that kills my 35P.
I use the MagnetoSpeed when I am looking for my max pressure load and to verify that my OCW load is is giving me the MV I'm looking for.
I use the MagnetoSpeed when I am looking for my max pressure load and to verify that my OCW load is is giving me the MV I'm looking for.
timelinex, You're pulling my leg, right? Exactly how much does a 2800fps bullet slow down in 10 feet?
That's interesting. It must be a frequency thing, because my range is literally in the shadow of a 1000' TV tower and it causes no adverse effects. I would think that it is operating at a much higher power level and is probably frying us instead of just our chronographs, lol. I guess it is interferring with the chip controlling the clock, since the detectors are optical. Have you checked with Oehler, considering the prevalence of Cell towers, they probably have some experience with this matter. Maybe there's a way to shield it.
Do you remove the magnetospeed after verifying the MV? If not, does it affect your accuracy when running the OCW?
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While I am anything but an expert on the subject, transmitters and their towers can emit frequencies that extend beyond their intended ones. There's a term called 'standing wave ratio', that relates to the extent of these undesired frequencies. Some of those unintended EM emissions can mess with nearby circuitry (as when a nearby commercial radio station blankets the frequency spectrum). The FCC regulates such matters with some severity.
When that ratio is near to 1, very little interference is generated, but it can actually vary quite a lot.
Any circuitry can emit these blanket frequencies, and even nearby Fluorescent lighting is sometimes associated with metric circuitry (electronic scales, test meters, chronos) malfunctions, which can range from pretty obvious to quite subtle. That part of the boilerplate instruction manual guff about RF emissions we all skip right by is directly related to such issues. Circuitry running closely next to identical circuitry could be especially influenced in this way.
Greg
When that ratio is near to 1, very little interference is generated, but it can actually vary quite a lot.
Any circuitry can emit these blanket frequencies, and even nearby Fluorescent lighting is sometimes associated with metric circuitry (electronic scales, test meters, chronos) malfunctions, which can range from pretty obvious to quite subtle. That part of the boilerplate instruction manual guff about RF emissions we all skip right by is directly related to such issues. Circuitry running closely next to identical circuitry could be especially influenced in this way.
Greg
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I did my 300 Win development with Dan. I ran a normal OCW with a suppressor, running slightly north of book data.
I got really good data that looked right. Then I checked the MV with the MagnetoSpeed and the higher pressure loads to see if there might be another node. I compared my numbers with factory ammo MV as I went up in pressure. Only problem was my 220 gr 300 Win factory ammo was actually using a 190 gr bullet. I got really close but started cratering primers so I stopped.
Decided my 2750 fps MV on a 220 gr bullet with no pressure and tight groups was all I needed. Until I play with the seating depth!
I did ask Oehler about the cell tower and they told me they wouldn't be surprised if there was interference.
I got really good data that looked right. Then I checked the MV with the MagnetoSpeed and the higher pressure loads to see if there might be another node. I compared my numbers with factory ammo MV as I went up in pressure. Only problem was my 220 gr 300 Win factory ammo was actually using a 190 gr bullet. I got really close but started cratering primers so I stopped.
Decided my 2750 fps MV on a 220 gr bullet with no pressure and tight groups was all I needed. Until I play with the seating depth!
I did ask Oehler about the cell tower and they told me they wouldn't be surprised if there was interference.
Been using a 35P for a while, (I've ordered far more orange plastic from Texas than needs to be discussed). The accuracy of the 35P Is "self verifying" -as the second proof chrono is part of the system. The Accuracy is dependent upon two factors, the spacing of the sky screens and the range of the velocity measured.
Accuracy of the 35P
For example if your screens are 8ft apart, and your round is in the 3000fps range your error is 2fps, if your screens are 4ft apart the error is 4 fps. These are really good chrono's. Cry once-buy the 35P, you'll never regret it.
Accuracy of the 35P
For example if your screens are 8ft apart, and your round is in the 3000fps range your error is 2fps, if your screens are 4ft apart the error is 4 fps. These are really good chrono's. Cry once-buy the 35P, you'll never regret it.
The one thing I do not like about the Magnetospeed is that on some of my rifles it does change the POI. It also seems to cause a small dispersion in the groups so I can't or rather don't use it during a workup which would be nice at times but not needed as I just verify my velocity on the node I settle with. If you want to get good readings during a workup I would say that the Magnetospeed isn't the right chrono.
L
L
And they just left you with that? wow, I'm disappointed in them. Considering the prevalence of cell towers, I would think they might have some helpful advice for you, or at least leave you with, "We're working on a solution right now."
