Magneto Speed group displacemant

[Hondo]

Informal group displacement test with Magneto Speed bayonet attached.
6ppc 68 grain bullet 3340 fps. MV
Shot group without bayonet to establish zero at 100 yards.
Shot group with bayonet attached at the 6 o"clock position group moved up .330 ins. right .150

Shot group with bayonet at 9 o'clock group moved right .440 ins. down .210

Shot group with bayonet at 12 o'clock group moved down .440 ins. horizontal 0

Shot group with bayonet at 3 o'clock group moved down .300 left .160

These groups were shot with wind flags, which I'm trying to learn to read.
This should be kept in mind when looking at the numbers.
HONDO

 

[284driver]

Did it affect group size or simply location?

 

[Lapua40X]

My tests were similar. But keep in mind that using the MagnetoSpeed Chrono to obtain MV information and trying to obtain useful information about trajectory at the same time is an exercise in futility. I use mine to obtain MV data, then remove it (a task that takes about 30 seconds) for gathering shot placement data. Although I did find the groups displaced by about half an inch, the group size was consistent - more a factor of MV and shooter input than the MagnetoSpeed bayonet placement. The overall consistency of the MV data collected with the MagnetoSpeed, eliminating the introduction of "close" numbers often obtained from other open frame chronographs, makes me more comfortable with the SD figures I'm recording.

 

[Hondo]

Don't know if it was me groups seemed slightly larger.

 

[Hondo]

Lapua 40x I use my magneto speed similar to your method .
I was curious to see the results plus some members to the site were asking about displacement.

 

[ftrrookie]

With my Savage M12 F/TR .308 win the poi moves almost exactly 1" higher at 100yds with the MS mounted. I used a 1" grid target zeroed it without the MS then mounted it and the group moved up 1 square. I'm going to try it at 300yds. See how far it moves

 

[GSPV]

This one was shot at 100 yards with the Magnetospeed attached.

 

[bootlaceb]

Remember, the Magneto speed weighs in at about 5.3 Oz. With that weight hanging on the front of your barrel, you will OBVIOUSLY change the harmonics. So not shooting the same grouping, or same POI will be completely normal.
As said previously, it is there to check speed, and not group sizes.

 

[ryanjay11]

By separating the ability to shoot for groups and measure speed at the same time, the Magnetospeed makes you shoot more rounds through your barrel to get the same data.

When I first heard of it, I was impressed by the new technology used to measure the velocity. It is truly impressive. I used one and thought it worked great, but I don't think separating groups and the measurement of velocity is a step in the right direction. Hopefully someone will soon come out with a chronograph that uses the same technology, but doesn't need to be clamped to the barrel, or be within a few inches of the path of the bullet.

 

[6BRinNZ]

By separating the ability to shoot for groups and measure speed at the same time, the Magnetospeed makes you shoot more rounds through your barrel to get the same data.

When I first heard of it, I was impressed by the new technology used to measure the velocity. It is truly impressive. I used one and thought it worked great, but I don't think separating groups and the measurement of velocity is a step in the right direction. Hopefully someone will soon come out with a chronograph that uses the same technology, but doesn't need to be clamped to the barrel, or be within a few inches of the path of the bullet.

An arguable point, chronys that aren't an Oheler or PV21 class can spit out dubious results...pretty much why I got a magneto. I still use the "normal" chrony in load dev as I primarily go on paper results...the magneto is final confirmation...I used mine several times during club days out to 900 yards...to get data under real world conditions. I was able to hold the 10 ring using it.

I shot last weekend with a guy who has just started using molly. The first relay had some vertical and the second relay was better, he thought it might have been due to cleaning the barrel and the molly building up again. I said next time lets stick the magneto on and we can watch the fps as he shoots the club days to shed light on the issue. No extra shooting, no extra range days, can still compete but importantly real world data to help validate a theory. Priceless.

 

[19zip]

bozo699 mentioned these a while back.
SuperChrono Acoustic shooting chronograph.

http://forum.accurateshooter.com/index.php?topic=3813881.msg36219083#msg36219083

http://www.steinertsensing.com/pub_docs/files/SuperChrono-Data-Sheet.pdf

 

[Nomad47]

I recently got a 78 shot average with "real world" conditions over several days. (I shot a bunch of groundhogs with the MagnetoSpeed bayo attached.)
I'm sold on the MagnetoSpeed. I develop my loads with the bayo attached and ALL subsequent shots are with the bayo attached. Gives me a record of EVERY shot.

 

[birdguy45]

I, too, wouldn't give up my MagnetoSpeed (MS), even though I also have a ShootingChrony Beta with the printer option. What I find remarkably handy is the ability to change the MS from gun to gun while the range is hot. I shoot at a private range where the cease fires are called on average about every 45 minutes. In that time, I can mount the MS on my .308, fire ten rounds for speed, remove the MS, fire a few groups for grouping tests, and repeat the process for either another load on the same gun, or do the same process on another gun.

I do find that the groups drift up at about 1 MOA toward 11:00 with my .308, though as others have noted, the groups stay about as tight as without the MS on the barrel. Of course, YMMV depending upon your gun and barrel. I also find that the MS is far more consistent than the ShootingChrony, probably because of the latter's sensitivity to light and shadow. Likewise, the MS works indoors under fluorescent lights, something the ShootingChrony won't do without the artificial light shields (another ~$100).

I still use my ShootingChrony for my semi-auto pistols, as there isn't a suitable way to mount the MS on the reciprocating slide.

All in all, there is a place for both types of chrony.

Walt

 

[desertc]

I, too, wouldn't give up my MagnetoSpeed (MS), even though I also have a ShootingChrony Beta with the printer option. What I find remarkably handy is the ability to change the MS from gun to gun while the range is hot. I shoot at a private range where the cease fires are called on average about every 45 minutes. In that time, I can mount the MS on my .308, fire ten rounds for speed, remove the MS, fire a few groups for grouping tests, and repeat the process for either another load on the same gun, or do the same process on another gun.

I do find that the groups drift up at about 1 MOA toward 11:00 with my .308, though as others have noted, the groups stay about as tight as without the MS on the barrel. Of course, YMMV depending upon your gun and barrel. I also find that the MS is far more consistent than the ShootingChrony, probably because of the latter's sensitivity to light and shadow. Likewise, the MS works indoors under fluorescent lights, something the ShootingChrony won't do without the artificial light shields (another ~$100).

I still use my ShootingChrony for my semi-auto pistols, as there isn't a suitable way to mount the MS on the reciprocating slide.

All in all, there is a place for both types of chrony.

Walt

I realize this is an old thread and in the last three years many others have encountered the same issues. I'd never have bought a Magnetospeed had I read them all. Here is a decent test and separate issue.
I just fired 14 rounds that were carefully prepared. They were all neck turned, selected for runout < .001, for neck wall thickness .015± .0005. They were loaded with 4451 weighed to < .05 gr, BR2 primers, Hornady ELD-M 140 selected for weight and bearing surface. 5 of the 14 were further sorted from the 14 for case variation. I was looking for Velocity variation contribution to vertical error and used a MagnetoSpeed V3 while shooting. I shot 4 from the 9 not-case-sorted group, then the 5 -sorted, then the 5 non sorted left. After the 5th shot, I noticed the MagnetoSpeed was further forward by an inch than I usually mount it and moved it back 1”on a very heavy barrel. The POI jumped up just over 1 moa and the next 9 stayed in a 0.18 moa group. We’re shooting at 1100 yds on plates that are only 1 moa center to edge. The MagnetoSpeed now seems useless for load development. I can use it to get average velocities and then shot groups for average POI and use 20x more ammo than a device which could be used for both at one time.


We don’t have a problem with nearby shooters. I own the range.