Chronographs part deux

[Turkeytider]

Well certain barrel, bullet,powder combos have nodes where they shoot better than others so it’s kinda important in the grand scheme of things..to me anyways it may very for others.

Good point.

 

[Varminterror]

how important is 8 fps either way in the grand scheme of things ?

Well certain barrel, bullet,powder combos have nodes where they shoot better than others so it’s kinda important in the grand scheme of things..to me anyways it may very for others.

I've described in several threads the differentiated applications where shooters/reloaders would be at risk of false signals when using the Athlon vs. the Garmin, and ultimately, as long as a shooter collects all of their comparative data within a single day without powering off and on, the Athlon will yield appropriate comparative results. The offsets seem to be intermittent, at least for the 3 units I've used, from one shooting session to another, so shooters which capture one load one day and another load another day would be at risk of inconsistent offsets from one session to the next spoiling the comparison. But within a given day, you can see that - minus the slightly increased volatility - the offsets track consistently with the other units. You might not find exactly the same speed for the node (not that scientific scrutiny of real world rifles supports velocity nodes, or nodes in general), but the relative performance of one load vs. another would be consistent.

Of course, the problem remains with small sample sizes - what I saw with the 30, 50, and 100 round sample sets I fired across these units would occasionally converge, so I'd see very similar SD's and ES's, with the Average MV simply shifted by the offset. In a few rare instances, all 6 chronographs would agree on the Average MV within +/-0.1%, 2-3fps, and the SD's and ES's would be very similar. On other sample sets, the SD's and ES's would be very similar, but the Average MV's simply offset by the recurring 5-20fps offset. VERY strangely, in some of my data sets, the ES's and SD's (simplified parameters) would seem very similar for all 6 units, but we can visually see higher volatility in the data set for the Athlons.

If a guy is doing a velocity vs. powder charge ladder in the Satterlee/Audette methodology, all fired within the same session, I'm not sure I think any of these units would identify a different "flat spot" (which we know isn't really a node, but is just anomalous, statistically certain probability), so any of these 3 models can deliver the same performance for that test, as long as a shooter/reloader is firing enough shots of each charge for the data to be relatively meaningful (aka, not just 1, 2, or 3 shots per charge weight).

 

[ptf18]

I really like the Seahorse/Evergreen cases with pluck ‘n pull foam. The #56 fits the Garmin and Athlon units, while the 1” deeper #57 fits the LabRadar LX. These fit the chronographs, their tripods, an ARCA or Picatinny gun mount arm, a battery pack, and their charging cords, and offer waterproofing as well as impact protection. These are $30 with the foam on Amazon. Scheels sells a rebranded version with topo-map camo black shell with laser cut foam inside (only holds unit, tripod, and cord, no gun mount slot) for $40.

I keep the charging cords curled under the tripods, and I have a “credit card” shaped/sized portable battery pack laying underneath the right side foam.

# 57 with LabRadar LX at our left, #56 with Garmin at middle and #56 with Athlon at our right.
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The Athlons do include a rigid softshell case, which is quite nice, but it doesn’t have room for the gun mount. Many folks may consider that a $30 advantage for the Athlon.

Thank you!

 

[PhilC]

Here's a couple pics of the zippered hard side Athlon case (5x8 notepad for reference) plenty adequate for my needs.