V3 Magneto Speed POI Change?

[Dragoon300]

The distance to the projectile path / bore should be the same regardless of barrel diameter by using proper shims.

 

[can1010]

you need to properly shim bayonet and the fact when you use side discharge brakes vents muzzle blast away from bayonet and your impact still changes. I have even tried with and without the brake and it still changes almost the exact same amount

 

[AZHTR]

Good info thank you all for your input!

 

[whirlwindjml]

I bought the red shims from magneto speed. They have like 1 degree taper built in.

 

[Dragoon300]

I have not done any testing, but I think the distance from the muzzle may be important too. It seems like further would be better given the knife like angle on the rear of the Magnetospeed bayonet.

 

[MNbogboy]

It mostly changes POI. It seems to me that if I shoot a fast cartridge like the 22-250 the difference is smaller than if I shoot a heavy bullet in a .260 or .308.

Poi always seems to be high and away from the bayonet. I've clocked the bayonet on the barrel & the target follows exactly.seems 3 to 7 inches is normal for most of my barrels Heavy barrels show this less
Groups tend to be smaller with bayonet attached and it acts somewhat like a tuner by adding weight to the end of the barrel.
Yes both POI & group size is affected. Some use zlenzs law as an explanation.

 

[new2mud]

I bought the wiser mount and I'm not really that impressed to be honest. I have the picatiny rail mount and it's just really hard to get a tight enough mount up to keep it from moving. On my 7 SST I have to fix the positioning after every shot, every few shots with a lighter cartridge like the .223. Maybe the ARCA mount would be better? Also the support from the seller is non-existent, I've never received a response to questions I've asked.

If you want a rail mount solution I'd look at the MKMachine mount, way more robust and not too much more expensive.

Personally I don't worry about accuracy when I'm concerned with getting velocity data. But here's a pic of the shift I got off bullseye at 100y with my 7SST.

hmmmm—that's odd. I have received very prompt responses from them. Perhaps your email went to spam? Give them another chance?

Not sure why your pic mount isn't locking up solid (or is it the strap to mount the sensor to the carbon fiber tube?). I use mine on everything from soft shooting subsonic loads up to magnums and don't have any issue with it staying solid.

With the Wiser mount keeping the MS off the barrel, I have kept it on for the last 3k rifle rounds I have shot, because...data. Easy data.

 

[dbohntr]

My DTA SRS has a heavy barrel that is much more rigidly mounted than most rifles. I found very little to no POI shift with my Magnetospeed, but it would shoot loose causing erratic readings. I like to get as much data as I can, so I shoot with it most of the time and log velocity with environmental data. I made my own adjustable aluminum picatinny mount for mine, end of problem!
In my opinion the Magnetospeed is simple, reliable and accurate. It is small enough to carry in your pack, and will give accurate velocity data in the field for hunters and military snipers. Adding a better mounting system allows you to obtain velocity data while grouping or testing with no POI shift.
Lab Radar is exceptionally nice for data gathering, providing more than just velocity. However, it is not as simple to use and carry with you.
For me, I think the Magnetospeed is a must have, and Lab Radar is better suited for more in depth data generation and load development.

Could you post a pic of your homemade mount?

 

[Dragoon300]

Could you post a pic of your homemade mount?

Glad to, I made it to be adaptable to a wide range of guns, here are three. I also wanted it to be rock solid.

I also wanted it to pack as small as possible because I believe it should be carried where ever you go to confirm velocity.
I shoot with it most of the time to gather as much data as I can. It does not effect accuracy or group size.

 

[dbohntr]

Thats great. You should sell them.

 

[new2mud]

That mount looks amazing!

 

[Dragoon300]

I would have liked to, but they would be more than what most people would care to pay. And when I heard Magnetospeed was going to bring out a V4 with a mount, I figured the time was passed. They are a great unit though.

 

[KSAv8r]

Everyone.....reading some of the responses about POI shift. I would like to suggest you are using the MagnetoSpeed for a purpose it was not designed for. During load development, whether you are using a LabRadar, Chrono, or MagnetoSpeed, you should be collecting speed data only to determine nodes where the bullet speed stays approximately the same as the amount of powder increases. This is usually where you will also find a small extreme spread (ES) and standard deviation (SD) of the 3 or more shots taken at the same powder charge. Point of impact or accuracy makes no difference at this point. After finding the speed node, load 5 rounds at +/- 0.1 grain increments above and below the center of the node and re-shoot using your MagnetoSpeed, LabRadar, or Chrono to confirm which powder charge gives the best speed with the lowest ES/SD. You don't need to worry about bullet speed again unless something changes, like changing lots of powder, lots of bullets, primers, brass, etc.

Now you are ready to start playing with bullet seating depth to tune your rifle for best accuracy. LabRadar, MagnetoSpeed or Chrono not needed so POI shift is not a factor. If you are trying to work with bullet speed and accuracy at the same time, you are likely wasting reloading supplies and your time plus will likely be chasing your tail. Change one variable at a time and record your data.

Some will argue that you should do a bullet seating test first before selecting a powder and charge weight, which is OK. Both processes will arrive at the same place from testing we have done. We have both a LabRadar and MagnetoSpeed. Personally, I prefer the MagnetoSpeed since I have had way to many shots where the LabRadar failed to capture any data or the LabRadar triggered when a person at the range next to us was shooting . We finally went to using the JKL Trigger and it works better, but not perfect. With an AR type rifle, letting the BCG go into battery will cause the LabRadar unit to attempt to capture a shot, which has to later be deleted. I can confidently say if the MagnetoSpeed is setup properly, it has never failed to capture a shot for us. No wasted time at the range and no wasted reloading supplies, which you all know are in very short supply these days. YMMV and to be up-front with everyone, we have no contacts or financial interest in either company and do not sell either product.

Hope this is of some value to you all. Good luck with your load development.

 

[Dragoon300]

Everyone.....reading some of the responses about POI shift. I would like to suggest you are using the MagnetoSpeed for a purpose it was not designed for. During load development, whether you are using a LabRadar, Chrono, or MagnetoSpeed, you should be collecting speed data only to determine nodes where the bullet speed stays approximately the same as the amount of powder increases. This is usually where you will also find a small extreme spread (ES) and standard deviation (SD) of the 3 or more shots taken at the same powder charge. Point of impact or accuracy makes no difference at this point. After finding the speed node, load 5 rounds at +/- 0.1 grain increments above and below the center of the node and re-shoot using your MagnetoSpeed, LabRadar, or Chrono to confirm which powder charge gives the best speed with the lowest ES/SD. You don't need to worry about bullet speed again unless something changes, like changing lots of powder, lots of bullets, primers, brass, etc.

Now you are ready to start playing with bullet seating depth to tune your rifle for best accuracy. LabRadar, MagnetoSpeed or Chrono not needed so POI shift is not a factor. If you are trying to work with bullet speed and accuracy at the same time, you are likely wasting reloading supplies and your time plus will likely be chasing your tail. Change one variable at a time and record your data.

Some will argue that you should do a bullet seating test first before selecting a powder and charge weight, which is OK. Both processes will arrive at the same place from testing we have done. We have both a LabRadar and MagnetoSpeed. Personally, I prefer the MagnetoSpeed since I have had way to many shots where the LabRadar failed to capture any data or the LabRadar triggered when a person at the range next to us was shooting . We finally went to using the JKL Trigger and it works better, but not perfect. With an AR type rifle, letting the BCG go into battery will cause the LabRadar unit to attempt to capture a shot, which has to later be deleted. I can confidently say if the MagnetoSpeed is setup properly, it has never failed to capture a shot for us. No wasted time at the range and no wasted reloading supplies, which you all know are in very short supply these days. YMMV and to be up-front with everyone, we have no contacts or financial interest in either company and do not sell either product.

Hope this is of some value to you all. Good luck with your load development.

Basically I agree with your procedure, however I believe the more data you can acquire, (velocity, POA / POI & environmentals) the better you can evaluate the consistency of the load and identify issues and changes. And with the cost of high performance ammunition, both factory and hand loads, I want to get as much for my money as possible.

I too believe the Magnetospeed to be the most fool proof and reliable option just as you pointed out. And it will work well as you recommended, just as it comes from the factory. To take it to the next level where it doesn't effect POI, it needs to be mounted off the barrel.