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Ballistic Calculator instead of Chronograph
- Thread starter Jinx-)
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Mikecr
Well-Known Member
No that chrono was bad. Buy a better chrono.
Actually, just assume your next slightly more expensive chrono sucks also, and buy an even better one.
Or, go ahead and buy the BEST chrono you can.
They are that important.
Actually, just assume your next slightly more expensive chrono sucks also, and buy an even better one.
Or, go ahead and buy the BEST chrono you can.
They are that important.
What Mikecr said. I never said all chronographs were capable of producing consistent, reliable, and credible data. Even the ones that are still have to be operated properly to get correct velocity data.
That topic is discussed in the Thread I provided the link to - above. The only way to calibrate a chronograph is to have additional chronographs or test equipment that is also capable of recording velocity, and shoot over the other equipment at the same time you shoot over your chronograph. The calibration would involve increasing or decreasing the spacing of the skyscreens until the chronograph is reading consistent with the other units.
Now if the Oehler company/folks would allow us to take our chronographs to their facility for testing along side of some of their premo units, adjustment of our skyscreens to calibrate our chronograph data to their data would be straightforward.
But chronographs come in varying quality, like every other manufactured electronic product. And even the good ones can break, malfunction, or provide some false data even when they're in tip-top shape. Which is why you need at least two units in order to identify the bad data that crops up every now and then, from the good data that is normally received with a quality chronograph that's being operated properly. My 2 cents.
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J E Custom
Well-Known Member
Obviously not.
There are several things that will give false readings of this magnitude. Muzzle blast and shock
wave from having the screens to close to the rifle.
If you research the load data the velocity should be within +or- 5 to 10% of the listed velocity.
If it is more than that you need to look at your setup and if possible compare your velocity
in another chronograph.
If your ballistic calculator tells you you need to come up 4 clicks from 100 Yards and you will be
on at 1000 yards do you believe it?
J E CUSTOM
I thought those rails were to close, the front rail got blown by the blast, but I was told it should be close to the muzzle. Anyway I didn't believe readings chrono gave me. Sierra list H4831 SC with 59.2 grains going 3100 fps and I had 61 grain load... That should get at least 3160 fps but I would take 3100.
joe0121
Well-Known Member
I've thought of sticking the chrono in front of my target, just gotta make sure I have a good zero so I don't shoot my chrono. gun)
J E Custom
Well-Known Member
For the realy big rifles, a blast shield will help. I set the front screen 12 to 16 Feet from the muzzle.
And on your velocity, remember a lot of the velocity/Data in loading manuals is calculated with
optimum numbers and very little actual real world testing.
Also each barrel may give different velocities from the test barrel used depending on length
and bore quality.
One way to check the velocity of a hand load is to compare it with a factory load that list the
velocity on the box, It will probably be slower in your rifle because it was tested under the
best conditions. I have only seen one or two brands of ammo that reached the listed velocity
(Just barely). but it does give you a bench mark to start with and with good velocities you can
get good BCs for your bullets, Then your drop charts will be very dependable.
For load development using the chronograph I can rule out a load with just two shots (If
the SDs are way apart there is no reason to continue testing that load because it will not
be suitable for long range.
As you can tell I am a big proponent of the Chronograph because it can give you lots of
information and save you lots of money, Plus if you have one with a printer you have a
permanent record of all of your loads.
So don't give up on the chronograph.
J E CUSTOM
SBruce
Well-Known Member
In my experiences, 300 isn't far enough to validate velocity by only using a program. We have to have a rifle that shoots basically "one hole" at 100 to know our TRUE zero, We also gotta know the exact height of our sights/scope before the ballistic program will be dead on at 300. I've often seen discrepancies at 300 from what the programs say, even with cronographed loads. I always concluded it was because of the close range "zero" not being exact.?
Now, that being said.....if we zero ~ 100, shoot at 300 and record drop, then shoot at 500 and record drop, then we can use the ballistic program to get close on velocity. It takes a big difference in BC to make much difference in drops when we're talking 500 and less, so the velocity is the biggest determining factor of difference in drop between 300 and 500 IMO.
As others have mentioned, a crono is a great tool to have. A cheap one may not give real reliable ES and SD's, but it will get you close on velocity at least.
rinodods
Well-Known Member
That's pretty funny if you were blowing the screens off. No way you are gonna get a good reading. Like was mentioned earlier stick that thing out 10+ feet and give it a go. Wonder if the chrony even still works. lol
No way you are gonna get a good reading. Like was mentioned earlier stick that thing out 10+ feet and give it a go. Wonder if the chrony even still works. lol
