Magnetospeed vs Labradar, a test.

[todbartell]

Controls for the lab are not as easy as the magneto, I couldn't go from the measuring screen back to the home screen without restarting the unit.
Batteries for the lad did not last long. Yes, it was cold, but even then. A rechargeable battery pack would be a #1 upgrade.

the labradar is a bit confusing to use. To go back form the "measure" screen to "home screen" you have to hold the cross hair button for 2 seconds.

^ this is the way to get back from the "measuring screen" back to the overview/menu

And the USB power bank is the best thing to power the LabRadar. It goes through AA fast!!! USB powers it for hours on end and you just simply plug it in when you get home and it's good to go!

 

[Ron AKA]

I did this ladder without any chrony at 300m during the fall, so I was pretty sure where the node would be.
The group it produced at 100m was about 1" tall, 1/4" wide. Just a ragged line of touching holes up the paper. I tried plotting each one, but couldn't see any distinct trend. Really not surprised, given that it was only 100m.

Keep in mind that to do a proper ladder test you need to record the elevation of every shot and the velocity of every shot. The purpose is to identify the sweet spot velocity. Also you cannot use a chronograph that attaches to the barrel as that changes the way the barrel vibrates. Here is a good article on how to do a Ladder Test. The author did not graph elevation, but I find it very helpful in identifying the sweet spot velocity. Here is a quick graph I did of his results. I would conclude the true sweet spot for his gun is at 2800 fps, from this graph.

 

[Alpheus]

I do ladder tests for all my load development, this particular load I had tested at 500m during the fall, so I knew where the chrony's should indicate the node being.

 

[rick357]

That depends on the rifle and barrel. My 6x47L has a 26" medium palma barrel, 0.900" at the muzzle, and it makes no difference to the PoI. Same with my truck axle F-class rifles.
My Sako 85 has a nice pencil hunting barrel, and the 100yd zero wonders by 1-2" when I strap on the magnetospeed. That, and the 7RM recoil makes the chrony slowly slip towards the muzzle with each shot, got to watch out for that.

Wanders on my Ruger 77/44 too. I found that a 3/4 - 1" wide strip of rubber about 2" long (think bicycle inner tube or something similar) under the strap around the barrel works wonders.

I think the POI change has everything to do with the change in barrel resonance. Those big barrels have a lot of mass and adding the Magnetospeed doesn't change the resonance a lot. Those skinny little hunting rifle barrels are more of a tuning fork and adding that weight out there just has to change things.

So saying, glad to see the comparison of measured speeds vis-a-vis the LabRadar and Magnetospeed. I've had my Mag for a couple of years now and it has been just superb. The only time it has missed reading is on the Ruger 77/44 and I suspect it was due to the slippage of the device due to recoil. Once the rubber went on to give the strap that extra little bit of grip on the barrel, it has worked perfectly (so far).

 

[H4831]

Great info and nice to see that the two best options in the market right now provide near identical results.

The magnetospeed bayonet will affect sporter contour barrels. No change on my heavy varmint contours.

One nice benefit we found with a cranky barrel, adding the bayonet tamed down all problems. A weight of similar weight was added and that barrel is now shooting like a champ.

Sometimes, there are positive collateral benefits to a weight on the muzzle.

Jerry

The reason sporter barrels are tamed by the bayonet hanging on them, is because they were not bedded with pressure under the barrel at the forestock.
With six pounds, or so, pressure under the barrel they hold poi just like the heavy barrels do.

 

[Mystic Precision]

The reason sporter barrels are tamed by the bayonet hanging on them, is because they were not bedded with pressure under the barrel at the forestock.
With six pounds, or so, pressure under the barrel they hold poi just like the heavy barrels do.

That would work if the stock never changed... but since they do, I free float all my barrels unless the rifle demands attachment to the stock (like the M1A).

Good idea though.. wish it worked....

Jerry

 

[redrams9]

I'm a little surprised that there isn't a bit more love for the Labradar?
I have owned both and sold my Magnetospeed after trying out the Labradar.
The Magnetospeed electronics are a tiny bit easier to use but after using the Labradar for several range sessions, it is very easy to use and actually prefer its screens and methodology to the Magnetospeed. Overall I'd say the usage screens are so close, that it's a wash on that point.
Where the Labradar absolutely crushes the Magnetospeed is in use and application. What a pain to have to attach and then take off and reattach the Magnetospeed to every barrel! If you only had one gun, one barrel it might not be so bad but I am always testing several guns, and switch barrels, that the Magnetospeed swapping would take up half my range day.
The Labradar, once you get used to where you place it in its sweet spot, never misses a shot, and I can read and use the buttons on it without even getting off my gun now. Plus it takes ZERO time to use it one the next rifle. Plus my buddy can use it while I'm reloading or recording info, and then simply place it back on my bench and I'm good to go again. We have also set it between us when we've been shooting prone and it will register either guys shots back and forth. To me the ease of use, super quick set up, and no time lost makes it no contest.
I researched battery packs for the Labradar and bought a 30$ rechargeable pack for it on Amazon, and it will last easily 3-4 full day range sessions between charges now too.
The Magnetospeed is a great little unit but the Labradar simply is quicker to set up by far, easier to use, and multiple rifles and users can use it all at the same time with no extra set up required.
Plan to use it indoors and tune up my handgun reloads this winter as well, which is impossible for the Magnetospeed to do.
So for me, Labradar 100% of the time is the clear better choice. The Magnetospeed is in no way a bad unit, and I did like it, and for the "one gun, one barrel" guy, it is the cheaper option by a bit, but this is the only instance I feel the Magnetospeed holds it own against the Labradar.
Just my opinion and experiences in having and extensively using both. Ymmv.

 

[Ron AKA]

I do ladder tests for all my load development, this particular load I had tested at 500m during the fall, so I knew where the chrony's should indicate the node being.

If you think a "node" is where powder charge increases but velocity does not increase, then I would suggest you are mistaken. If you increase powder charge and don't get more velocity, all you have identified is a problem, not a node. Need to start searching for reasons you are not getting more velocity.

 

[Alpheus]

If you think a "node" is where powder charge increases but velocity does not increase, then I would suggest you are mistaken. If you increase powder charge and don't get more velocity, all you have identified is a problem, not a node. Need to start searching for reasons you are not getting more velocity.

I define a node as where the change in velocity is relatively insensitive to change in powder charge. The link you posted above says "For long range shooting in particular, using a load that produces the least amount of vertical variation is vital". Don't you think that consistent velocity round to round is the biggest factor in achieving minimal vertical spread? What do you define a node as?
I shot this ladder at 300m, and put 4 rounds at 35.8 and 36.0 into a group with a hair over 1/4 MOA vertical, IIRC. If I get results like that, I'm not going to be concerned by how much the velocity is increasing or not.
Not all of my rifles show such a pronounced pause on the chronograph; this is probably the most abrupt one. This is also a very narrow one, but since it has appear in two separate tests, I am pretty confident it is a sweet spot.
And I have also stated that my previous ladder was done without the magnetospeed attached, and that this barrel does not experience an appreciable shift with PoI when the bayonet is attached.
And lastly, this string of shooting was not strictly a ladder test, it was a chronograph test.

 

[RonR]

...If I get results like that, I'm not going to be concerned by how much the velocity is increasing or not.

...but since it has appear in two separate tests, I am pretty confident it is a sweet spot.

These are my thoughts and experiences. I couldn't explain it to make it register for another poster.

Thanks for posting...Regards Alpheus
Ronr

 

[Ron AKA]

I define a node as where the change in velocity is relatively insensitive to change in powder charge...

Please explain to me how it is physically possible to keep increasing powder charge and not get any increase in velocity? What possibly could cause that?

 

[Alpheus]

I don't know the physics behind it, I'm not a ballistician. All I know it that every one of my rifles has a range of powder charges, sometimes even 2 or 3, where the rate of velocity increases is a lot slower than the rest of the charges. And top long range shooters the world over say the same thing.

One other thing, increasing powder charge and your velocities start decreasing is a high pressure sign, although typically you'll see primer and bolt lift signs beforehand. I don't know the physics behind that either.

 

[Ron AKA]

I don't know the physics behind it, I'm not a ballistician. All I know it that every one of my rifles has a range of powder charges, sometimes even 2 or 3, where the rate of velocity increases is a lot slower than the rest of the charges. And top long range shooters the world over say the same thing.

Have a look at the example below of three different bullets where vertical displacement is plotted vs velocity. Possibly in one of the three there is a smaller than average increment of velocity with a stepped powder charge. I would suggest it is just the normal randomness of data, and indicates nothing about a sweet spot. However when you look at the relationship between vertical and velocity, all three bullets show basically the same thing. Vertical POI is quite insensitive to velocity over the range of 3400 to 3430 fps. Velocity increases but POI does not. That is a true node or sweet spot from a ladder test.

 

[Alpheus]

On your chart, see how the data points that have minimal vertical are also closer together in the X-axis? That's the slower rate of velocity increase.

 

[Ron AKA]

On your chart, see how the data points that have minimal vertical are also closer together in the X-axis? That's the slower rate of velocity increase.

You must not be looking at the same chart. That is three different bullets, and I see no close spacing on the yellow or blue. Yes there is one closer spacing on the red, as I noted in my post. However, that is simply the variability of velocity due to loading. It would be a pretty miserably poor test if looking for close velocity spacing could only predict the sweet spot for one out of three bullets tried.

What is very noticeable from the graph is that the Berger 68 produces more velocity for the same load than the other two bullets. Don't have the data, but I suspect there is a difference in bearing surface or bullet diameter.