Jeffrey Van Zandt
Well-Known Member
yes it will change but is not for sighting in just for getting your rounds dope speed, SD ect once you have that info take it off
V3 Magneto Speed POI Change?
- Thread starter AZHTR
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baldhunter
Well-Known Member
I use my magneto speed for checking velocity only.I can affect your POI a lot.If I want to run test loads for velocity and grouping,I use my ProChrono.
Citified
Well-Known Member
As others have stated, it does change POI. In my rifles it is about
1 MOA. But for the cost, the unit really provides great data. If money is no object, Labradar.
1 MOA. But for the cost, the unit really provides great data. If money is no object, Labradar.
milo-2
Well-Known Member
I have never seen more than 2.5" of deflection at 500 yards with any barrel using magneto. I recently zeroed a scope with one hanging off the end, it was miniscule. I can bang steel all day long w/o a zeroed scope, or with a magneto hanging from the barrel.
We like to invent problems, if work is that critical, pull it.
We like to invent problems, if work is that critical, pull it.
Agree.......use your MagnetoSpeed (or LabRadar) to determine bullet speed nodes of where the speed changes very little between small changes in powder charge (small ES & SD). After that, change bullet seating depth to find the best accuracy.
I have also started with a medium charge and determined the best bullet seating depth to get the best accuracy followed by using a MagnetoSpeed (or LabRadar) to find the the best bullet speed node. Both methods seem to work but I prefer the first method.
I think the key, as mentioned by several, is to only change one thing at a time, verify your results and keep good records.
cjuve
Well-Known Member
Like others I have seen vertical poi shifts with the magneto speed of varying magnitudes, to me it is of no consequence. I usually don't use the chrono until the final stage of load development and then it is just to gather a couple velocity's. I strictly use POI at longer ranges to find powder charge, seating depth is done at 100 and then fine tuned at range.
jrg
Well-Known Member
Rick Richard
Well-Known Member
We have mostly commented on POI shift, however I failed to mention too that I have experienced not only POI shift but groups opening up. Again, that is why I only use the MS to collect velocity data after I have achieved a desirable load.
SteelBanger
Well-Known Member
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.
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.
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lgwatson
Well-Known Member
Mine changes. Usually about 1" high and slightly right at 100 yards. Depends on rifle and load, but always changes a little.
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.
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.
whirlwindjml
Well-Known Member
This has been my experience. The bull barrels are affected the least. I went labradar as well. I don't have primers to waste. I need as many bird killed with one stone as possible. Time/fuel/distance make the labradar a no Brainerd. The magneto speed is accurate though. I noticed the speed wasn't identical to labradar but both were close and both showed consistent es and sd as each other.
I agree with Rick. Remember, you are using the Magneto Speed to determine MV, not to refine your POI.
It may change barrel harmonics, but I also think the bayonet deflects some of the air that is pushed out by the bullet upward to deflect the bullet slightly. Hence, the closer the bayonet is to the bullet (sporter barrel vs bull barrel), the worse the deflection. It would make sense that this effect is least for heavier bullets, as some have said above.
