Has anyone here used this type of chronograph? I've got a decent Crony Gamma model with the digital printer and it works ok with my 50 BMG if I post it about 7 yards down range.  Also if I I don't fold it all the way out or it starts getting to dark or cloudy on me then I get strange readings. . I've been getting emails from Len Backus at http://www.longrangehunting.com/store/magnetospeed-v3.html About this new fangled It is a barrel mounted Cronograph that does not use light nore is it affected by muzzle blast. I'm thinking it would give me better readings on my 50 BMG for better long range programing. Anyone have an idea? I want to get the most accurate velocity for messing with long range shooting.

Man I wanted to try this design with my 50 and had ordered one from Brownells but after watching a couple of videos from the manufacture I got to thinking it might not fit on a big muzzle brake with the 50.  So I called them and sure enough it will not work with most of the 50 BMG muzzle brakes.  We need to pester the company to design a model that will work with our 50's.  I had to cancel my order.  Bummer!

I am avoiding this style chronograph.  I think it will do you a disservice.

Follow my logic here:

It may accurately and repeatably give you correct velocities and still be USELESS to you for working up a load.
Why?
Because attaching weight at the very end of the barrel is the fastest way to change where the velocity node of the barrel is!!!

Find node, remove the sensor... how much has it now changed?  ;)

It would be fine for spot-checking an already worked up load for desired velocity or standard deviation,
but I would not trust it for working one up.

(You only need to tweak a guitar string a little to change its pitch a lot)

On a 50BMG that would not even be an issue as with the diameter of the barrel, the thickness of the steel and the V3 being only a couple ounces the barrel wouldn't even know it was there. Now if you were to put it on a pencil thin 24 inch .223 barrel then I would have some concerns but I don't think it would affect the velocity at all more of just the point of impact.

Anyone that shoots a suppressor knows that the weight will affect point of aim but with most of my suppressors attached it usually either is exactly the same or a  slight increase in FPS over what it was without the suppressor and a suppressor weighs A LOT more than the V3.

I have both types of chronos and the V3 shows nearly identical to my Beta model. That being said I don't know if I would even put it on the .50. With the measuring portion being right at the end of the barrel the .50 BMG would subject it to a lot of expanding gas pressure and I don't know how long it could take that kind of punishment.

I could care less about any change in velocity observed, or point of aim, I'm talking about effecting the frequency the barrel resonates at and the effect of tuning ammunition to that frequency.

By changing the mass of the barrel ( by attaching things to it ) you change its resonant frequency.

THAT is the entire point of chronographing loads on a 50BMG in the first place: to find that specific frequency.

If hitting a pizza box at 1k is your goal this does not apply to you.
If you want to shoot groups on the box it does.

Totally agree with PP9000,

I shot .22LR comp for several years. Ya, only 50 yrds, but the bull was .5" and if you break the line big hit on your score from 100 to 50. My barrel was like .9xx and with a knock off of the BOSS barrel tuner. it did not take much to pass through the resonant node. So no matter how much steel you have in your barrel. Just remember the projectile is much heavier than that little .22 pill. And the energy in a 50BMG round going off is much more than a lowly .22LR. So, what PP9000 says has a lot of merit.

You do both understand that we use the V3 for finding velocity then you can take it off the gun right? No reason to leave it on while shooting your micro groups at 1000 yards. The fact that you are even talking barrel harmonics and velocity nodes makes you the less than 1% shooters that worry about such things and it sounds like this chrono is not for you if you want to track what speed your bullet is doing while shooting groups. If what the OP was asking is finding the best way to find your velocity on a 50BMG I agree with both of you that the V3 is probably not the way to go as the part that measures the velocity is right in the path of the exhaust gas and while it would work better than your gamma model I don't know how long it would last taking that kind of abuse.

After finding out the V3 would not work at all for my 50 BMG I got turned on to a new type of chronograph and it's got me VERY interested A friend gave me some into on a unit they were showing at the shot show. It works on the principle of radar and is called "Labradar". Their website is www.mylabradar.com and Richard replied to my email quite promply when I asked him about working with the 50 BMG, 338 Lapua and other guns with large muzzle brakes. His reply really got my juices flowing and have me with the the urge to get it asap. This is a great idea without having to go down range and disrupt a bunch of people shooting plus it does not get mixed up on which gun is supposed to be chronographed while at a public range and it does not touch the barrel at all. . It will even clock your bullet at longer distance like 100 yards with will really help you figure out the ballistic performance of a given type of bullet. It should be out this fall and while I normally try to avoid the first new models of any new product this one has me so intrigued that I've got to get one as soon as they let them out.
When using a chronograph it really makes a difference on having the proper data for ballistic programs that will not work without accurate feet persecond data on the bullet and load your using. I've found that with the proper data plugged into the KAC Bullet Flight Military, Version 4.2 Ballistic computer on my Android phone will put me on the paper with my 50 BMG at just about any reasonable range as long as I can feed it the proper cross wind data.

I'm pretty happy with my V2.  I haven't noticed any POI shift at 200yds with either my Windrunner or the Sharps.  The V2 just barely clears the brake on the fifty, but no damage to the sensor in a hundred shots.  I did have to put some metal tape around the strap to keep the brake blast from melting it.  I'll be interested in the reviews when the radar chrono comes out.

Thanks for the reporting the real world use. I was worried about putting it on my .50 since it was over $300 I didn't want to take the chance of damaging it. Nice to hear that it can take the expanding gas without any problems. I didn't think it would have any effect on accuracy since it is so light I didn't think the barrel would even notice it was there.

My muzzle brake is longer than most and I would have to strap it around the brake where the hot gasses would directly impact the strap.  I really like the idea of the Labradar and I'm planing on posting a report on it after I get one.  

I do understand the indicated velocity with it attached WILL BE DIFFERENT than with it not.

The very reason for chronographing loads is made irrelevant by attaching that device.
The velocity you are seeing is largely useless for anything but drop calculations.

POI has NOTHING to do with velocity standard deviation NOR grouping.



Locating your node-for-your-load will not make a huge difference.
Using cases from the same lot will not make a huge difference.
Uniforming flash holes will not make a huge difference.
Weight sorting projectiles.powder charges within .1 grains.
Correcting primer pockets.
Hand loading.

Add it all up and it makes A HUGE FUCKING DIFFERENCE.

If you want to be a hack blasting at rocks, that's fine.
I have blasting grade ammo for that stuff.  Its lotsa fun.

But:
This is a technical forum.  People come here to learn the right way to do stuff.
They've spent an awful lot of time and money to get this far.
I'd bet more than 1% want to get their moneys worth out of their investment.

Not going to get in an argument with you. Sounds like this device isn't for you. But I could probably count on one hand the people who have even ever said in my life "velocity node" even though I have been around shooting for the last 42 years. You obviously want to take any variable out of the equation to get your best shot and that is admirable that you take the time and energy to do this but for anyone else that is not shooting 1,000 yard competitions Neck turning, pre heating the gun and ammo, figuring out each individual case volume, uniforming flash holes, weighing each piece of brass, etc is a waste of time as shooting a pizza box at 1,000 yards is outstanding for 99.9% of the shooting population.

You do also understand that the 4.5 ounces that you put on the end of your barrel is about the same torsion of 7 mph wind drag creates on a 36 inch 50BMG bull barrel?

You also say for certain that the velocities "WILL BE DIFFERENT" but provide no proof of that statement. Have you tested the V3 in such a manner as to figure it out? I have found that with or without the V3 on my other rifles that I cannot find any SD differences in it being on or off. So, in my experience with BOTH the standard chrono and the V3 would be that it didn't affect my velocity.

4.5 Ounces? ..!

Holy crap. I had no idea it was that heavy.  

That will absoloutly cause issues.
I'm not going to buy one to do a comparo for you, but...

The next time you see any benchrest guy worth his salt
tell him you can hang a quarter ot a pound on the end of your barrel with no measurable effect.
Watch his face when you do it.  If he doesn't crack a smile his eyes will be watering.

Just for giggles I shot my Sharps with and without the V2 at the same time through the screens of my Oehler 35.  No significant difference between the displayed velocities were observed during ten rounds in each run (20rds total).  Now my Sharps barrel is quite a bit thinner than my Windrunners, but accuracy was not affected.  Granted, I was using peeps and a rest on the 100yd target, but that settled my concerns.  I think PP is getting barrel harmonics confused with velocity.  It doesn't take much to do that to most barrels, but muzzle velocity will not be affected unless you are changing gas flows impinging on the bullet.  For me, I'm going to treat each of my chronos as accurate, and reserve the Oehler for my guns less suited to the V2.

Like I said before this is probably not for you yet you still seem to want to chime in even though you have never laid your hands on the chrono in question.

So, what you are saying is you really have no idea of how it will effect your velocity. You have no proof of how the gun will preform with it on yet you say for certain that it will change the velocity? Considering I have tried it with and without the V3 on my barrels and found no difference in velocities and so did the last poster I believe you should consider what you think is true with what is actually been tested before you spout out nonsense on a technical forum.

You do understand that a stiff breeze will put a lot more pressure on a standard long range shooters .50BMG barrel than the V3 would?

This!  As a V3 owner as as well as a typical styled chrono owner there is NO velocity difference.  PP9000 would do well to go over to the snipershide.com and educate himself so he doesnt look so silly.