Tuesday Tech Tip – Labradar and Light Loads

By Mark V. Lonsdale, STTU

The training never stops and the goal is to learn something everyday. Yes, we have all learned that the radical left social democrats are willing to destroy our 1st and 2nd amendment rights (free speech and the right to bear arms respectively), but we have known that for some time. So let’s focus on shooting.

375 CT Labradar2

The Labradar is a pivotal part of TRS load development and competition preparation

Today I was doing load development with my Marlin 1895SBL 45-70 Guide Gun, and hit an anomaly that I had not seen. When doing load development for hunting or tactical rifles, I usually begin with proven factory ammunition to get a baseline muzzle velocity (MV).  In this case I began with the Hornady LeveRevolution 325 FTX that I had tested in the past. Three years ago I had tested several factory 45-70 ammunitions and the Hornady 325 FTX was the most accurate, but still kicks like a mule.

325 FTX


Top: Marlin 1894 .44 Magnum. Bottom: Marlin 1895SBL 45-70 Guide Gun 

Running a Labradar, the Hornady factory ammo logged an average MV of 1,887 fps and my handloads of 50 grains of IMR-3031 came in at 1,735 fps. The problem, and focus of this tech tip, began when I tried to chronograph some light practice loads.

I began by loading 41 grains of IMR-3031 with the hope of coming up with a load that was pleasant to shoot and chrono’ed around 1,500 fps. So you can imagine my surprise when I began getting readouts of 3,000+ fps, or no read-out at all, even though the recoil was considerably reduced. The only thing for frustrating than an “unable to read” on the Labradar, is a reading of twice what it should be. I had only 10 rounds loaded up with this light load so never was successful at getting an accurate MV.


Hornady 300 grain hollow points loaded down to 41-50 grains of IMR-3031 for light practice loads. Will be working up loads with VihtaVuori N130 and N530 in the near future.

Thinking about this conundrum on the drive home, I had an inkling of the problem, but shot off an email to Richard at Labradar just to confirm my suspicion. He promptly responded with the advice to set the Labradar on pistol mode for anticipated muzzle velocities below 1,600 fps. Problem solved. So I now have additional light loads loaded up and ready for the next trip to the range.

Conclusion – Tech Tip: Move your Labradar from rifle mode to pistol mode when chrono’ing rifle loads below 1,600 fps. This would include 44 magnum, 45 LC, or any other cowboy action shooting loads.

Stay tuned for future 45-70 load development with VihtaVuori N130 & N530


Labradar 45-70


About Mark V

Dedicated shooter, seeker, traveler, teacher, trainer, educator
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