“The Benefits of Chronographs”


This Week’s Tips or Tricks…




Q:  What are the benefits of using a Chronograph and why should I consider investing in one???


A:  Chronographs play a very important role in determining the stability and deviation of velocity of ammunition which can result in big accuracy enhancements or degradation down range…so we are going to take a look at how a MagnetoSpeed Chronograph can help us out here.



First….why a MagnetoSpeed Chronograph specifically?  The MagnetoSpeed Chronograph was selected for this discussion not just because we are an Authorized Dealer, but rather because of the huge benefits and advantages which the MagnetoSpeed Chronographs provide over the competition.  Unlike Shooting Chrony, Oehler, and other chronographs available on the market today, MagnetoSpeed chronographs use a patent pending electromagnetic sensing method to determine bullet velocities rather than the traditional series of optical sensors.  Now why does this matter?  Chronographs that use the traditional optical sensors suffer from the effects of shading and narrow optimal sensing windows which can result in large variances in muzzle velocity readings.  If you look at the pictures below of the MagnetoSpeed versus the Oehler and Shooting Chrony both shown in the second picture below, you will notice that the MagentoSpeed is a barrel or rail mounted sensor (as shown above mounted on a rifle and handgun) that doesn’t require an elaborate setup of optical sensor arrays, tripods, cables, printers, and etc. that can take as long as 15-30 minutes to setup, but rather the MagnetoSpeed can be installed and setup within just 2-3 minutes on average and you’re ready to begin shooting.  Now, how is the MagnetoSpeed not affected by an optimal window like others?  As you can see below, the MagnetoSpeed is installed on the barrel or rail of the firearm so that the bullet passes parallel just above the electromagnetic sensor for a uniform sensor reading on each and every shot.  When we look at the Oehler or Shooting Chrony below as a comparison, you will see the two orange lines on the right chronograph that represent where the bullet must travel through the optical sensor array in order to provide the optimal sensor reading.  So if you use a traditional optical sensor array chronograph…now we have to worry about shading and the height of our shooting rest, muzzle, and the height of our chronograph and pray that we get a uniform passing of the bullet through the sensors….yikes, what a pain right!





Have you, a friend, someone you know, or have you even just heard a story about someone else’s day at the range that was abruptly ended with a DESTROYED chronograph because it was forgotten to take into account the height of the chronograph tripod, shooting rest, the scopes height above the bore, or even you/they just accidentally pulled the shot and ended up shooting a hole right through the chronograph sensor(s)?  Now whether it was the ~$100 Shooting Chrony or the $500+ Oehler Chronograph it really doesn’t matter anymore at this point…because all that you/they have left is a very expensive span of little tiny pieces strung everywhere at the range!?!?  With either the MagnetoSpeed Sporter model at just $189 MSRP or the top-of-the line MagnetoSpeed V3 coming in at just $399 MSRP, you won’t ever have these headaches, problems, or worries again!


Since we have now discussed the differences between the MagnetoSpeed and other traditional optical sensor chronographs, let’s now take a look at how a chronograph can help us make a difference in our reloading and accuracy now that we can get passed worrying about all those cloudy days or having to setup our chronographs in just the right lighting conditions.  So why do we chronograph rounds…two words….UNIFORMITY and CONSISTENCY!  You have by now heard me state over-and-over that the key to accuracy is consistency and eliminating as many variables and errors as possible because any errors or variability will just compound upon each other and thus resulting in a very non-conducive environment to getting the best accuracy possible out of our reloads.  So what information can a chronograph tell us about our ammunition and reloads?  Let’s have a look at the data that the MagnetoSpeed Chronograph provides us when archived to the onboard Mirco-USB card:


In the rows and columns of the *.csv file that our MagnetoSpeed Chronograph archived our shot data at the range, we will find the following values:


Series: This is the LOT or series of ammunition or reloads that we tested.

Shots: This tells us how many shots were taken in this LOT or series.

Min: This tells us the minimum velocity that was recorded during our Series.

Max: This tells us the maximum velocity that was recorded during our Series.

Avg: This tells us the average of all of our velocities over the entire Series.

S-D:  This tells us the Standard Deviation of our velocities over the entire Series.  [*Note: lower is better.]

ES:  This tells us what the ‘Extreme Spread’ or what our Maximum minus Minimum Velocity for our entire Series was.  [*Note: lower is better.]


Now that we know what each of these values represent, how do we use this data to understand, gauge, and improve our potential accuracy for our ammunition or reloads?


Ok, first let’s compare the major ‘players’ here one against the others for the data shown for the rounds tested out of this particular test from a .223 Rifle:




Above we can see that Series 4 resulted in the lowest extreme spread in velocity and thus had a much smaller Standard Deviation from shot-to-shot.  Series 3 had the worst extreme spread in velocity and thus had a significantly higher Standard Deviation from shot-to-shot…so let’s now look at the effects of these data points on our point of impact by going back to our Kestrel 4500NV with Applied Ballistics and run a few scenarios to see just how much of a difference velocity deviation and instability will potentially affect our shot groupings!



Now that we have converted all of these muzzle velocity data points into an anticipated point of impact (POI) that accounts for the effects of the Standard Deviation of our muzzle velocities for each particular shot series, you can really start to see why a Chronograph can be extremely beneficial to our reloading process and accuracy!!!  Let’s first look at the POI analysis from Series 1 above where we had the second best S-D at just 24 fps.  If we are shooting the ammunition or using the reload recipe for Series 1, we can anticipate our shot grouping to be roughly 3.15” ES at 500 yards at best…so not bad being just over 0.5 MOA grouping at 500 yards right?  Well, now look at Series 4…if we cut our S-D in half, we may also cut our shot grouping in half as well!  If we reload ammunition using the reloading recipe used for the Series 4 data with just a 12.2 S-D in muzzle velocity, then we can now anticipate a 1.35” ES at 500 yards which is just slightly over ¼ MOA at 500 yards…NOW WE ARE BREEDING ACCURACY THROUGH CONSISTENCY FOLKS!!! 


Now…let’s just say that you didn’t use a chronograph when developing your loads, but you happened to decide to choose the reload recipe for Series 3 based purely upon your 5-Shot grouping at 100 yards.  Since Series 3 had an S-D of 70 fps, look at the ES of Impact at 500 yards with that load….nearly 2 MOA is now the best ES you can anticipate at 500 yards…WTF???...”I’m getting rid of this rifle” is what you’re now thinking because this just flat out sucks!


So…now that you have seen the numbers and data showing how a chronograph can help you in further developing your reloading recipes in that quest for the ‘Ultimate in Accuracy’, but now you’re just not quite convinced that $xxx dollars is worth spending because “the reloading manual already tells me what the Muzzle Velocity is for FREE and that is close enough”…well here are a few thoughts for you to ponder as we close this week’s segment out.


Did you know that most of the reloading manuals that provide your Muzzle Velocity of (xxxx fps) were gathered from a test conducted in a controlled environment typically with a 24” barrel?  Now why is it important to know this?  Let’s say that your favorite hunting rifle happens to have a 26” barrel instead of a 24” barrel like the documented muzzle velocity was acquired from in the controlled atmosphere for the reloading manual…did you know that the muzzle velocity can vary as much as 20-40 fps per EVERY 1” that you add or subtract from your barrel compared to the barrel tested for that reloading manual data!?  This means that if you anticipate that the muzzle velocity for your load is at 2560 fps (as per the manual)…that your rifle with the 26” barrel may actually be pushing between 2600-2640 fps in reality!  On the flip side, if you only have a 22” barrel, your muzzle velocities may only be 2480-2520 fps in reality so be careful when ‘guestimating’ your muzzle velocity!  You have seen in the above charts just how much a [+1] or [-1] S-D difference can make in your point of impact (POI) results down range…so by ‘guestimating’ your muzzle velocity on top of chasing a reloading recipe that may have a poor S-D…you may just end up chasing your tail in circles and find yourself down a long and dusty rabbit hole costing you a lot of time and money in bullets, powder, brass, and primers just because “the manual said so”…so don’t get caught in that trap if you can avoid it!  


Please Note: Broken Box R LLC is an Authorized Dealer of MagnetoSpeed Chronographs, so if you have any questions regarding any of the MagnetoSpeed products discussed above or if you would like to purchase one, please give us a call or email us today at sales@brokenboxr.com!




Do you have a Tip or Trick regarding reloading that you would like to see posted?  Please send us your Tip(s) or Trick(s) and we will see about getting them posted!




Written By:  Kyle R. CEO of Broken Box R LLC


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