That explains it then.
Run over a Chrono and out the correct figures into a ballistic app
223 ballistics - not what it says on the tin ! - would welcome any advice
- Thread starter Mark45acp
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Run over a Chrono and out the correct figures into a ballistic app
Thats one very accurate gun thenespecially with that barrel length.
Get it chrono ed , and forget about what the box says, my advice, for the ranges you are shooting at, is zero at 75 yards
At 3000fps , BC of .23 and scope height of 2.5 " you are half inch low at 50 and 160 yards, half inch high at 110, and 2 inch low at 200.
If your MV is higher (it wont be a lot) even better.
It’s a 1/2 moa, accurate but not shockingly so, barrel length doesn’t seem influence accuracy
Just seen this - as most have said, it's almost certainly the gap between reality and marketing on the velocity front! Well, that and your short barrel having the same effect. I put some Remington factory through my .222 (20" barrel) a while ago and it was more than 250fps below the advertised speed. Still very accurate though.
Depending on where you are in Sussex, I have a chronograph if you're intrigued (once the world is a bit more normal etc).
Depending on where you are in Sussex, I have a chronograph if you're intrigued (once the world is a bit more normal etc).
You need to do a proper drop test. Look it up.
Drop tests are more accurate than a chrono muzzle velocity for the shorter range sports shooter, because they deal with the decrease in BC as velocity decreases.
With your short barrel there is no knowing what muzzle velocity you’re really getting, and the factory BC will not apply because you will probably already be below the first G1 threshold.
If you do a proper drop test, I guarantee you will get the right information for your set up.
Drop tests are more accurate than a chrono muzzle velocity for the shorter range sports shooter, because they deal with the decrease in BC as velocity decreases.
With your short barrel there is no knowing what muzzle velocity you’re really getting, and the factory BC will not apply because you will probably already be below the first G1 threshold.
If you do a proper drop test, I guarantee you will get the right information for your set up.
This""". Ballistic calculations should always be trialled in real field conditions and confirmed in practice. Plus cr@p in equals cr@p out. You need accurate imput data
Yes, and no. You've got it a bit too simple I'm afraid.
A "drop test" (as you call it) is just DOPE (Data On Previous Engagement) and, while accurate, is only applicable for that particular environment (temp, humidity, atmospheric pressure). Hence why we have BC's and ballistic calculators; calculators that alter the BC as velocity degrades and factors in environmental changes from when the ballistic calculator was "trued".
Realististically, you start with a BC (which is derived at a standard velocity) and then gather velocity data. Then calculate the ballistic curve (which will attempt to degrade or increase the BC based on the velocity difference). Then "true" the ballistic curve (best done at extreme range, so that the changes are discernable) by altering the BC until the curve matches reality (again, at long range). The difference here, is that a ballistic calculator includes environmentals, and can therefore alter the curve as the environmentals change.
As to the accuracy of chronographs; with today's magnetic or pulse doppler chronographs, they are about as accurate as a person can get, short of being in a lab. Definitely accurate enough to support an accurate ballistic calculation. And certainly accurate enough to be empirical to predict drops. It's the BC that is the issue.
ETA: I would also add, that Hornady's BC's (as are most manufacturers) are fairly accurate when you understand the length, twist and environmentals of the test gun/environment. To say they are rubbish, is just blaming a company for the person's own ignorance. Ignorance of how BC's are calculated, and how the velocity of the shooter's gun can be markedly difference than that of the test gun. Yes Tikka, I'm looking at you with some of your slow barrels... (And for the record I love Tikka's, but some calibers are very slow. 6.5mm for example).
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I know all of that.
But look at the application, the range and the rifle/cartridge.
What you’re talking about is what the ELR guys do. I was careful to note “shorter range sports shooter”....
To be fair, you couldn’t complicate matters more if you tried!
Okay...
Let me put it this way then. BC doesn't mean crap at short range as long as it's close, and velocity does matter more. If you know the velocity and the zero range, then the drops based off the factory BC will be more than adequate for "the short range sports shooter". (eyeroll)
Is that simple enough for you?
If you're "short range shooting" than why are you even worried about uber accurate drops? FFS, talk about idiotic remarks....
Let me put it this way then. BC doesn't mean crap at short range as long as it's close, and velocity does matter more. If you know the velocity and the zero range, then the drops based off the factory BC will be more than adequate for "the short range sports shooter". (eyeroll)
Is that simple enough for you?
If you're "short range shooting" than why are you even worried about uber accurate drops? FFS, talk about idiotic remarks....
I needed a good laugh this morning, thanks @MarinePMI!
It’s all good mate, you can stick to your theory and I’ll stick to my practical experience.
Take a step back and look at what we know of the problem, and the fella we’re trying to help. Start at the beginning.
There is much to be said about practical experience.
I needed a good laugh this morning, thanks @MarinePMI!
It’s all good mate, you can stick to your theory and I’ll stick to my practical experience.
Take a step back and look at what we know of the problem, and the fella we’re trying to help. Start at the beginning.
He’s not shooting deer, he’s shooting foxes.... See, I told you to start at the beginning!
Guilty as charged. My b...too many threads to keep track of...He’s not shooting deer, he’s shooting foxes.... See, I told you to start at the beginning!
