paul scrobohaci
Member
I had access to 2 Labradars and thought that testing them one against the other may reveal random measurement errors, as opposed to systematic/procedural errors (errors they both make the same way because they use the same, possibly faulty hardware, firmware, ... etc).
I set them on either side of my rifle and set them on different RX/TX channels so they wouldn't interfere with each other.
I used my Sako TRG 42 in 338 Lapua Magnum with handloads of 84.2 G Vihtavuori N565 and Scenar 250 G HPBT bullets. The brass had been shot a number of times in same rifle, annealed each time, processed with a Redding FL S-type bushing die. The primers were Federal large magnum rifle match primers gm215m.
I shot 3 groups of 10 shots each. One was with S&B brass, crimped necks, second was with PPU brass non-crimped necks, third was with Lapua brass, non-crimped necks.
Results:
Average muzzle velocity values ranged from 2685 fps to 2735 fps. MV ES ranged from 30 to 43 fps in each group of 10.
On over-10-shot-average MV, one Labradar consistently measured 3-5 fps higher than the other. Call the fast measuring FAST, the OTHER SLOW.
On individual MV, I saw the largest outliers where:
1. FAST measured 10 fps OVER SLOW, once.
2. FAST measured 2-3 fps UNDER SLOW, twice.
I set them on either side of my rifle and set them on different RX/TX channels so they wouldn't interfere with each other.
I used my Sako TRG 42 in 338 Lapua Magnum with handloads of 84.2 G Vihtavuori N565 and Scenar 250 G HPBT bullets. The brass had been shot a number of times in same rifle, annealed each time, processed with a Redding FL S-type bushing die. The primers were Federal large magnum rifle match primers gm215m.
I shot 3 groups of 10 shots each. One was with S&B brass, crimped necks, second was with PPU brass non-crimped necks, third was with Lapua brass, non-crimped necks.
Results:
Average muzzle velocity values ranged from 2685 fps to 2735 fps. MV ES ranged from 30 to 43 fps in each group of 10.
On over-10-shot-average MV, one Labradar consistently measured 3-5 fps higher than the other. Call the fast measuring FAST, the OTHER SLOW.
On individual MV, I saw the largest outliers where:
1. FAST measured 10 fps OVER SLOW, once.
2. FAST measured 2-3 fps UNDER SLOW, twice.
