WildcatBullet 338 cal 350 gr elevation at 2000 yards ???

[DANTEC]

Matt

from pure metrology I agree than 0.25 moa from scope turret is a bit " un accurate " measurement system BUT that a usefull way to compare and get a delta or gain valiue between two things

300 SMK a well know bullet wich is define by 6DOF equation fly so able to receheck with several methods
and
the ??? datas of the new wildcats bullets

so between to do nothing and speak hollow , making a first computation is not to bad , and far better than to enter in dream story as 408 balanced fly theory proven with unreachable dopller datas

often logic and simples methods are better than mystery and Harry Potter respices

good shooting

DAN TEC

[abinok]

Like dantec said,
Its not the most reliable way to generate data, but it does allow data to be compared to some extent, especially when comapring it to a well modeled bullet like the 300gr SMK.
Like dantec said, its better to do a rough comparison than to just set around and dream about it. Hopefully when Brent gets some 350s over the chronys, we will have some hard numbers to go by.

HEY DANTAC, I just showed your modified "california legal" 50 BMG to a friend, I never can remember the name of it, but he is convinced you are a genius!

[Brent]

Okay, I'll throw one more stick in the spokes here: The BC for the 300gr SMK in my tests does not agree with the number stated here... It was something in the order of .787 or there abouts at about 3000 fps. I'll see if I can find what I came up with in the tests using the 43.

Along the lines of what Matt said, I think drops compared from the same rifle/scope combo is a much better way of comparing the two bullets.

GG would do well to set down with his rig and determine what his click values truly run throughout the range of adjustment. The distance multiplies the error and in his case (1500-2000 yards), it could be very frustrating to find out that it is a slight turret miscalibration keeping the first shot predictability in various conditions elusive.

I've got a 32" barreled 10 twist 338/378 Wby to compare the 300gr SMK and 350gr WC. Not too much longer and we should be able to get set up at 500 yards with the chronos for some testing.

I hope the 350's group well enough to keep them directly over the chrono at 500 yards.

Does Richard make any .510" bullets?

[Brent]

338/378 Wby 4.1" OAL 300gr SMK, 32" Pac-Nor bbl.

This is only a 100 yard test and might prove a little different BC numbers at 300 yards or more. The measured distance to the acoustic target is very critical and BC's can be off considerably if not measured to within 1/10 of a foot. Obviously because of this, the further away it is placed, the less error there will be with an identical distance measurement error.

Next time I'll test with two chronos, which I have not done with the 300gr SMK.

A little info on what you see here and how it works:
The acoustic target uses three acoustic microphones, each one located on a point of the triangle frame. The mach wave from the passing bullet triggers each "stop" sensor. The start screen located on the chrono rail starts the clock. With a starting and stoping point, the time of flight to target(TOF2T) is measured. With a known MV, and TOF, the downrange velocity (Vel-T) and BC can thus be calculated.

TOF is also captured in another section for each individual microphone in order to triangulate the exact bullets path/location through the three sensors.

With the use of a chamber attached strain gage peak pressure (Peak) is also calculated.

You can see the difference here is, the acoustic target relies on TOF and MV to determine BC and Vel-T, where two chronos know the exact MV and Vel-T to calculate the BC. The distance measurement of two chronos is thus much more forgiving and not nearly as critical.

[Matt27]

Brent

I believe Richards does make 50cal bullets.
Shoot him an email

[goodgrouper]

[ QUOTE ]
GG would do well to set down with his rig and determine what his click values truly run throughout the range of adjustment.

[/ QUOTE ]

Yes, I suppose I could, but in all reality, testing bc with this back door approach at 2000 yards is just plain inaccurate anyway.

I could tell you how many clicks it took to get to 2k today, and then tomorrow it would take more or maybe less. If the wind switches from tail to head and it just added another 3 minutes to the drop. That is just too much interference to accurately calculate anything. The only real way to do it is with a Model 43 or a Doppler radar. This thing that Dantec is supposedly running is just for kicks and giggles. Are you done with it Dantec?

[DANTEC]

I not agree with you

if you plan to measure ( metrolgy operation and not pretty display on a computer because display on a computer is NOT a true thing EXCEPT after to have check all step of the measure from adta aquisition , to A/D conversion to final sofware equation checking and software programming )
a velocity with a oehler 43 ( sound target ) you perhaps need to be sure of all atmospheric parameters because speed of the sound vary with air density
you need to carefully calibrate your sound target system for the velocity you want to catch because subsonic fly noise , transonic fly noise , supersonic fly is not the same
you need to calibrate to your sound target for bullet location and be sure than your measurement map give you the same reading data , so at 2000 yards where you shoot in your target ???
you need too to carefully check your instrumental velocity to the bullet velocity ( not really the same if you plan to reach the real accuracy in measurement )

now on my idea to compare things to things

you shoot at a know distance with a know bullet ( BC ) launch at a know velocity in a know atmospheric conditions
you get a elevation ( on turret ) to reach your target
all of that are true fact , parameters as tail wind ... can be forget )
you do another trails with another bullet
change is only bullet and velocity but you can record all parameters EXCEPT bullet BC so you can by computation get an good idea of the bc of the bullet you have shoot

and by computation you can find you BC bullet IF all your fly is in true supersonic velocity to stay in the straight aera of your drag curve and avoid transonic aera

as Dopller story/myth /dream/myhery

Doppler is costly to use that a fact
Dopler data need to be post compute by a software as PRODAS ( another $$$$$$ piece of equipement ) to get BC data and usefull data because raught dopller data is just a numerical file without any use without post computing
Dopler data need to be use ONLY by qualified engineer to not spread internet with dummy value or magic results

so to make a conclusion logic and engineering view of problem can allow to make pretty accurate thing without million of $ of equipement

as equipment I use I use impact target ( piezo sensor and measure time of fly between the muzzle and my impact , transmision time is calibrated with a 100 Mhz pulse generator to measure how much time my impact target signal ( during data acquisition and after data aquisition ) take to come back to my computer

I have more fun to make field instrumention than to make noise with costly shinny rifle and I am interesting first by true enegineering speaking .

good shooting

DAN TEC