View Full Version : Ultra II velocities?
2nd December 2007, 22:43
At the range today with a chrono and Ultra Raptor, I was shocked at the following avg. velocitites from 230 gr. loads:
Winchester FMJ white box - 375 fps
PMC FMJ Bronze - 395 fps
Cor-Bon HP - 535 fps
Is this sad performance normal for a 3" barrel? I don't much want to switch to lighter bullets. Does anyone manufacture a +P 230 gr. FMJ?
I'm pretty confident of the readings as the .357 Mag. and .45 Colt loads read as expected.
2nd December 2007, 23:06
I'd have to say that something is wrong. Velocity in the short barrel shouldn't fall off nearly that much compared to a 5 inch barrel. I'd give it another try.
One thing you might try is moving the screens back another couple of feet. You get a lot of muzzle flash with the short barrel, and the flash can be read by the chrono and distort the results.
3rd December 2007, 00:52
I think you must have had something on the chrono set wrong. My tests of multiple ammunition types and brands showed that, in general, compared to a government model you lose approximately 15 to 20 percent of muzzle velocity when shooting the same ammo through a 3" barrel. Your velocities are less than half.
Does your chrono have a setting for how far apart the two screens are? If they were 2 feet apart, ir it possible you had it set for 4 feet or 6 feet?
3rd December 2007, 13:51
Recently measured 750-760fps average 230gr WW white box thru my Kiber Ultra Covert II. Wolf came thru at 725 fps average.
3rd December 2007, 20:55
Thanks everybody, it'a a relief to hear that others fare better.
It's hard to imagine though, that the 4" .357 readings didn't suffer from muzzle blast interference, and the 3" Kimber did. Nonetheless, I'll try again further back.
Screens were set OK judging other cailber performance.
Incidently, penetration with all was 1.5 pressure-treated 2x6"s, which does seem to make 375fps a too slow reading.
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