Originally Posted by biggdawg
i run a one shot pressure/velocity check for the range of charges i think will work to get me ballpark with the chrono on then i load my desired ladder do my work ups then after i have chosen my charge i do a 10 shot velocity check with the chrono.
i can't do work ups with it on i have a huge poi shift.
I don't want to be a buzz kill, but have to put forth my .02 on this one.
Before I start, I will say that I rarely shoot at controlled ranges. I shoot at a self regulated range in a rural area - USFS land - so very different from busy regulated "city ranges". Therefore I am not restricted to access my chrono by a range master.
What is mentioned by Timber338 and bigdawg is the first thing I thought of when I saw the first Magneto. Anything touching the barrel can affect POI AND group size, but I see in a previous post someone mentions that it doesn't change their group size. (However your mileage may vary.)
I design products (actually designed and made my own chrono on a Vector board & wire wrap in 1985 using a Z80 processor as a hobby project - no big deal really), and the knowledge that POI and group size could be affected by something attached to the barrel steered me away from a design like that. As we see, it is actually causing the users to change their methodology of load development and fire even more rounds than a device that doesn't affect trajectory. ONE OF THE FIRST RULES OF PRODUCT DEVELOPMENT IS, DON'T MAKE THE USER CHANGE THEIR METHODOLOGY UNLESS THE BENEFITS ARE OVERWHELMING.
When do I use a chrono? A lot of the time! I use it for load development. I also use it to confirm velocities whenever any variable changes after I have a good load (primer, brass, trim length, annealing, etc.). I also use it to observe different atmospheric affects on the gun and powder (hot days vs. very cold etc.). I have put well over 1000 rifle rounds through my chrono in the last few years. (Hundreds of pistol rounds as well though for those I don't worry about the target- its just for speed testing. The Magneto obviously is a no go for testing pistol ammo.)
In all of these (rifle) tests I compare the target with the chrono data.
Cost of shooting is something to consider as well, especially if you shoot a lot of Barnes or other premium projectiles.
The convenience benefit is clear with the Magneto. Access to the chronometer at a regulated range would be a big plus and perhaps more important for many, robustness of operating in different lighting conditions. But for me that does not merit a change in load development and verification methodology. (Not to mention 2X-3x the cost of a standard design chrono, along with a significant increase in ammo usage/cost.)
Just my own humble opinion.
Have fun, be safe!