Need som opinion here-any left? Happy T-day.
Thanks;
joe b.
On Chronographs
I'm starting to write the chapter on chronographs for the CBA cast bullet book. I've had a Pact chronograph for 15 or more years. I've used it to estimate BC by measuring velocity at 2 ranges, and used that estimate to calculate sight settings for 600 to 1000 yards before going to those long
ranges.
That is about the only use I've ever had for a chronograph.
If there are any things I know about my chronograph and shooting, they are: (normal range of velocities)
Variations in velocity have nothing to do with group size
Individual velocities have nothing to do with where the bullet hits.
Higher velocity than average bullets can hiot higher or lower or eastor west of the center of the group.
Standard deviations of velocity calculated to 2 decimals with n = 5 are statistically meaningless.
n must >/= 30, like it or not.
I've chronographed thousands of bullets, written down the velocities, done some statistics to these sets of velocities, and learned nothing.
I think a chronograph is a waste of money and time.
Comments welcome.
joe b.
From John Bischoff (he must be wrong!)
I only acquired my first Chrony a couple years ago. It gave me a window into what was really happening with my handloads. The various handbooks list x grains of y powder and a z grain bullet for w fps - but one never knows if one is actually GETTING what the books say. Then too, if one wants to use a non-standard powder (H4831 in 222 Rem with a 60 grain cast bullet) to achieve a gentler smoother acceleration, the Chrony lets one know how well the stuff is working (2375 fps, a small SD, and 2 MOA).
One can use a chronograph judiciously to develop a load that is close to max with a powder for which there is minimal data, such as the surplus stuff available from GIBRASS and others. Or, one can verify that a moderate load with such powders really IS moderate.
I love chronographs.
John