Which shooting chronograph do you use?

[Shootin4fun]

Sorry for the last post...I had not yet read the ones talking about the MagnetoSpeed.

Ok, different modes for different bullets, etc. But I haven't noticed anyone talk about it affecting the POI or accuracy.

 

[Shootin4fun]

I have found similiar results using my Magnetspeed for a couple of months. I subtracted 10-20 FPS depending on the rifle used, which would then match my Oehler. I seems to match my Shooter apps calculated velocity loss difference between the 15ft distance of the Oehler and the MS sitting right in front of the muzzle. On several separate days, and two different rifles, the MS gave me FPS and ES which were within a few FPS. It's so precise that I have been able to determine the exact number of shots it takes to stabilize the velocity from a clean bore. I have also found that with both my rifles my group size and POI does shift with the MS mounted, so i dont combine the two processes, the only drawback. I may be just my rifles though. I'll likely sell my Oehler, this is great technology.

Sorry, I feel remiss/foolish now...So my assumption that the Magneto would change the POI and group size seems to be true according to Greyfox's experience. Just makes sense.

I would have been concerned about taking this one to market if it were my idea because I don't waste sending rounds downrange just to see the speed; I use all shots to determine accuracy and keep all targets. I would figure most guys do the same, but maybe not.

Designing a prototype is one thing, but its a lot of money to invest to go into full manufacturing and establishing a patent. Good luck to the Magneto guys though!

By the way, with the Pro Chrono, like Greyfox mentions with the Magneto, I can see exactly when the velocity stabilizes after a fully decoppered barrel (which I don't do between every shooting session). I can also see the smaller difference in a lightly cleaned barrel (with only powder fouling removed). Lastly I see the same velocities I last left the range with if I don't clean the barrel at all. (This is what I do before going out for the hunt- know my POI and leave it be!) All states of barrel show repeatable results.

D & X zone hunts start in 10 & 17 days...woohooo!

 

[azsugarbear]

Shootin4fun,

Some shooters report little if any change in POI with the MagnetoSpeed, while others have recorded a pronounce shift in POI. It seems that the heavier the barrel contour, the less the POI is effected.

For me, I will send one or two shots downrange to confirm POI and then quickly strap on the Magno to confirm velocity. I have found that changes in subtle changes in speed have a bigger impact down range. Doesn't bother me in the least to shoot one or two to verify my velocity.

My main reasons for buying the MagnetoSpeed were: 1) ease of use; 2) true muzzle velocity (not imputed from ten yards in front); 3) more consistent reporting of shots (much fewer error readings); 4) not dependent on lighting conditions.

 

[Shootin4fun]

Shootin4fun,

Some shooters report little if any change in POI with the MagnetoSpeed, while others have recorded a pronounce shift in POI. It seems that the heavier the barrel contour, the less the POI is effected.

For me, I will send one or two shots downrange to confirm POI and then quickly strap on the Magno to confirm velocity. I have found that changes in subtle changes in speed have a bigger impact down range. Doesn't bother me in the least to shoot one or two to verify my velocity.

My main reasons for buying the MagnetoSpeed were: 1) ease of use; 2) true muzzle velocity (not imputed from ten yards in front); 3) more consistent reporting of shots (much fewer error readings); 4) not dependent on lighting conditions.

Heavier barrel = less of an effect; makes sense and what I would expect. My tubes are all sporters at this point... and if the powder shortage keeps up, I'm not buying any more rifles!

Interesting, I don't see small variations (+/- 5f ps) in velocity making a significant difference downrange. My shooting ability or wind makes a bigger diff.

I use my Chrony about 12+' in front of muzzle so velocity is virtually the same as at the muzzle. Certainly close enough for ballistic tables to be right on. I don't get very many error readings but yes, when they happen they throw the statistics off...must calc manually and omit those but not a big deal.

Ease of use and not dependent on lighting seem like the strongest arguments to use a Magneto, especially if you're forced to shoot at a regulated range...my main one is not, its in the forest, but city ranges, ugh, setting up a unit in front of the firing line is a pain.

 

[Shootin4fun]

BTW, Magnetos are priced 2.5x - 3.5x the cost of what I paid for the Chrony, but of course to some cost doesn't matter.

Thanks for the good feedback/info!

 

[azsugarbear]

You are correct that 5 fps is not worth worrying about. What I do worry about is a more substantial change over a period of 100 shots. When a barrel begins to have copper/carbon buildup to the point that pressure/velocity begins to spike, I want to catch it right away.....even before it happens. The old style chromos were just too time consuming to set up, so I wouldn't check except every hundred rounds or so. Now I just strap it on for a shot or two just to make sure my velocities aren't beginning to go sideways on me.

 

[bigngreen]

Thee strongest point for the Magneto is how accurate it is and the ease of use is secondary to me. I have to to adjust my velocity from the magneto speed very little IF any to get my ballistics on, I'm saving sooooo many rounds and time dialing in rifle ballistics it's amazing. We have several Chronies and I've compared the data from them to the Magneto and about half the rifles it was close the others it was up to 100 fps of which is useless data IMO!!!

 

[Shootin4fun]

Interesting....BnG. Wondering how the Chrony could be off 100fps on some rifles but not on others.

In the last few weeks I've noticed my velocities dropping aout 60 - 80fps on loads that were done at a different time from each other but a very consistent recipe . I thought maybe I need to totally decopper, but more copper in the barrel seems like should cause higher velocities due to pressure and speed, not less. Then I started wondering if there has been drift in my Chrony. But I found some older rounds and they reported within 20 fps of what I had recorded.

So I have a few questions, though maybe off the topic of chrono for a minute...

1) Does there come a point where copper fouling causes maybe more pressure but a drop in velocity due to added friction?

2) Has anyone seen velocity reports change like that with the use of a single chronograph over time? They are digital devices so seasonal temp changes shouldn't affect them. The clocking signal is typically generated by a quartz "chip" though and that could be responsible for a 2% change if they get really hot or cold. But temps here have not been extreme; between 70 & 85 degrees.

I HAVE noticed that the new Winch brass I bought seems to be a little "slower" than the Federal I've been using all along.

It almost seems like the little Varget that i have left has become "weaker". I have never experienced this before.

I cleaned the barrel but not totally decoppered, loaded a test set .5gr hotter and plan to go out in the next day or so to see what happens.

 

[bigngreen]

I think being of has more to do with lighting condition, I've also noticed changed from setting it out with a gravel surface vs a reflective snow surface, I do most of my shooting in the evening after work and as the sun goes down I used to watch my velocities change, then I'd get an error and finally it's just not catch anything. My magneto speed give me the same velocities in every light condition, I've got data in rain and high winds that was good. My ES has definitely come down with the Magneto speed, I shot up a lot of components chasing chronies!!

 

[Shootin4fun]

Yes, I can believe that lighting conditions might have something to do with variations in velocities that I've been seeing lately. I don't use it in the snow much but since I shoot for hours at a time the angle of the sun changes. I am most often shooting in direct sunlight out here in sunny the Sierra Nevada mountains of California. I have never felt like I was chasing the accuracy of the Pro Chrony because my accurate loads are very consistent. Its just recently that speeds have dropped some so I'm considering everything and it may be the Chrony.

I wonder if the manufacturers have tried making them with IR sensors and found that to be a no-go. I would think the pills are surely hot enough at 12 feet from muzzle to register a signature.

Anyway, the main thing is to find an accurate load and get a reliable snapshot of velocity and consistency as another data point to determine downrange energy and if you can't shoot at many different distances and simply observe, to calculate drop.

 

[azsugarbear]

Could your change of velocity be possible due to a change in the temp of your powder/round. With some powders, a change in temp (not air temp, but ammo temp) could be the result of the change.

 

[Shootin4fun]

AZ- Thanks for the suggestion.

Actually, I've been paying more attention lately about keeping my ammo in the shade, thinking that I wanted to keep it more stable, but these loads have been so consistent over time that I didn't consider that in these latest outing where the velocities went down. That might actually have something to do with it. Its Varget which I understand to be pretty temp insensitive. I gotta go back and look at my winter records when its in the 30s - 40s.

I haven't been able to find any Varget for 9 months now but I have enough to get me through deer season so experimenting is taking a lower priority than scouting and target practice. I don't think 100 fps is going to make a difference to the deer but I do want to establish a valid zero out to 350 yards. I consider these loads good out to that.

(I don't know who's getting all the powder- all the stores say they are just not getting deliveries and when they do its gone immediately of course. If they're not getting it who is??)

Going out today or tomorrow to run final tests and final zero.

 

[azsugarbear]

Not sure if you have seen this:

[ame=http://www.youtube.com/watch?v=ZaXB2QgIRsg]SNIPER 101 Part 58 - Ballistics Tables - Muzzle Velocity Variation (1/2) - YouTube[/ame]

Parts 58 and 59 explain a lot about how temp effects velocity and by how much. It's a great series.

 

[royesses]

Magnetospeed V1 and V2.