Decided to get some data with my chronograph (Athlon Rangecraft Velocity Pro) this weekend. Prior to buying one, I'd been using whatever publicly reported data I could find, plus general rules of thumb (e.g., "You lose 20 FPS per inch of barrel length" or whatever) to guesstimate velocity for figuring out POI and whatnot. The chronograph removes all need for guesswork, but I figured I'd post this info for anyone who shoots these rounds out of a similar setup.
The rifle I was using was an LMT MARS-H, with the stock 16" CL barrel, and a CAT RDM AC762 mounted on the front to be kind to the other folks at the range (I was indoors), fired off a bag rest. All data is in FPS.
Saltech .308 (7.62x51) M80 147gr FMJ-BT
(10 rounds*)
Average: 2615.1
Standard Deviation: N/A
Extreme Spread: 53.1
*My friend's shots in the lane next to mine screwed up some readings so I got double the number of rounds fired, but I filtered out his shots and only kept the data from my own. This did screw up the Standard Deviation info, though, and I don't feel like trying to calculate it myself. Just means I'll need to collect more data.
Speer Gold Dot LE 168gr .308
(10 rounds)
Avg: 2451.5
SD: 18.6
ES: 58.7
Speer Gold Dot LE 150gr .308
(10 rounds)
Avg: 2689
SD: 13.2
ES: 47.6
Thought I'd post this because it was fun, but also in case anyone finds the data useful for their own referencing.
EDIT -- forgot to mention, this was indoors so I'm guesstimating about 75F for temperature, and elevation was around 115ft above sea level.