175g uld rbbt testing at 800 yards

[reed mosser]

you should try some 180 berger vlds at the same range and time and compare the point of impact. If you need a few to test i have some to spare. I too found that shooting the .224 100 grain rbbt at a 1000 that the b.c was actually closer to .525. The wildcats are a good shooting very accurate bullet but I don't think the b.c is as high as the vld designed bullets. There is a give and take for everything. Just my 2 cents [img]/ubbthreads/images/graemlins/smile.gif[/img]

[youarenotcrazy]

Not to steal the post, but I was under the understanding that Altitude doesn't effect bullet flight in and of itself, the Barometric Pressure decreases as you increase altitude and that is what causes different impacts.

If 25-06 was shooting @....say 2000' asl, the pressure standard on his ballistic program once compensated for the altitude would give it 27.53" Hg going by the standards... Had he the ability to take ACTUAL station pressure readings from his shooting location the altitude would be unnecessary and he could input the station pressure into his ballistic program and potentially come out with the correct B.C. calculation.

Supposing he was shooting @ 2000' asl and entered such, the program is going to use the standard 27.53" Hg (for that altitude)... if the actual station pressure that day was 28.53" his impact could be somewhat significantly lower.

That's how I understand the matter.

That said, I agree with Reed Mosser, you should shoot the 175 wildcats along side a known 168 Berger during the same session and run the numbers to see if the 168s still coincide with the ballistics program.

[CatShooter]

[ QUOTE ]
Not to steal the post, but I was under the understanding that Altitude doesn't effect bullet flight in and of itself, the Barometric Pressure decreases as you increase altitude and that is what causes different impacts.


[/ QUOTE ]

You are right. It is the local pressure that determines the drop - with most programs, if you enter local (station) pressure, you must set altitude to "0" feet AMSL, or you will get double the altitude, cuz the program also compensates at the same time.

.

[royinidaho]

Catshooter,

NOAA reports both local "Hg say 25.xx and sea level "Hg say 29.999. If I enter the 25.xxx and 4450' MSL is that the same as entering 29.999 and 0' MSL?

I don't have the exbal program yet but have been messing with an internet capability. Just trying to get a better understanding of things.

[bailey1474]

If you have some way of getting the station pressure (which is that 25.xxx in/Hg in your post) always set your altitude @ 0' on the ballistics calculator. They only time you will use altitude is if your using it to guestimate the pressure.

[remingtonman_25_06]

Dave- I might try and figure out how to do something like that. Maybe stick a couple pieces of posterboard together or something.

By the way, Hermiston is only at around 600-700 feet.

[remingtonman_25_06]

Roy- I never did much understand pressure and humidity, but I can somewhat see how it would have an effect. I know altitude has a little effect on things. I know this because when I go up in the blues which is 4500ft or so, my rifles usually shoot a couple clicks flatter then down at home where its only 600-700ft. I did bookmark that weather page, gives a little bit more detailed info, thanks!