drag, twist, and transonic flight.

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Don McDowell
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Re: drag, twist, and transonic flight.

Post by Don McDowell » Fri Apr 23, 2021 7:07 am

I am wondering what the dimes from the mile target look like compared to the ones from the 1000.
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powderburner
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Re: drag, twist, and transonic flight.

Post by powderburner » Fri Apr 23, 2021 7:43 am

Brice , i did. I started with two 30 and a grease cookie. And found the bases badly cupped, and distorted. Moving to 60s helped some but the bases still were not pristine adding another 60 solved the problem.
So it is compressing 106 gns of 1 f with a 60 , adding a 60, 3/16 grease cookie,and another 60.
I cant see good enough to compete but off bags on a bench with a scope it is a clean burning consistent using only a blow tube. This load will shoot all day without going nuts.
On hot windy days a few breaths down the muzzle are necessary before a string to maintain the accuracy
Dean Becker
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Kenny Wasserburger
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Re: drag, twist, and transonic flight.

Post by Kenny Wasserburger » Fri Apr 23, 2021 7:48 am

Indian headdress, is the best description as to how they look.

The angle of their impact is quite obvious also. The headdress is the bottom of the strike. As you can see the angle of the bullet at impact is visible. Contrary to the nay sayers, the mile match has been a interesting laboratory for insight into the long range effects on our bullets. Only thing better would be a radar to chronograph the bullet all the way down range. My lab radar is supposed to be good to over just 100 yards. Hopefully to test in next couple weeks, I think the data will prove to be interesting.

Even spin drift, it’s effects are very pronounced firing on a west to east axis, :shock: on the order of 8.5 MOA left sight correction. :shock:

As they hit the steel the bases cup, the ones that missed do not have that cupping of the base, I imagine it’s from the lead flowing back as the bullet strikes the steel.

Kenny Wasserburger
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Don McDowell
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Re: drag, twist, and transonic flight.

Post by Don McDowell » Fri Apr 23, 2021 8:06 am

That is very interesting. Thanks Kenny.
How far back from the target do they land?
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Re: drag, twist, and transonic flight.

Post by Kenny Wasserburger » Fri Apr 23, 2021 8:30 am

Don they are all within 4-6 feet of the target often right at the base, a few are further out.

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Don McDowell
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Re: drag, twist, and transonic flight.

Post by Don McDowell » Fri Apr 23, 2021 12:03 pm

That's interesting, as seems most of the dimes from the 1000 are 10-12 ft.
Tells a person there's still a boat load of momentum even at 1 mile.
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mdeland
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Re: drag, twist, and transonic flight.

Post by mdeland » Fri Apr 23, 2021 1:57 pm

I wonder how fast they are still going at a mile ? Looks like from the pattern of the lead splay out they are really pointed down at quite an angle.

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Re: drag, twist, and transonic flight.

Post by bruce m » Fri Apr 23, 2021 5:37 pm

here are some figures for kenny's bullet.
they are approximate as i have given the bullet a b.c. of 0.5, a weight of 520 gns, and a muzzle velocity of 1400 fps.
approximate as they are, it offers some idea.
at 1800 yds they are still doing around 700 fps and retain around 560 ft lbs of energy.
interesting are mach numbers.
600 yds mach 0.87
800 yds mach 0.813
900 yds mach 0.788
1000 yds mach 0.765
1700 yds mach 0.641
1800 yds mach 0.627
given that the transonic zone is defined as from mach 1.2 to mach 0.8, the bullet appears to go fully subsonic somewhere between 800 and 900 yds.
if it is still cracking at 600, this tells us that the sonic crack is still with the bullet below mach 1.0 or the speed of sound.
i have shot on electronic targets at 800 meters (880 yds) which rely on sonic shock to record, and it has recorded for 24 shots.
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Re: drag, twist, and transonic flight.

Post by powderburnt » Fri Apr 23, 2021 5:41 pm

FWIW, my Oehler Ballistic Program says a 535 gr bullet with a BC of .506 and a MV of 1450 will be at 716fps when it gets to 1750 yards. Peak of the path would be 138 ft at 950 yards. On the graph it looks like the bullet would be coming in at about 40 degrees at the mile mark. I'm a little surprised at the energy and velocity retained at a mile.

HG

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Re: drag, twist, and transonic flight.

Post by bruce m » Fri Apr 23, 2021 5:56 pm

either way, you wouldn't want to get hit by one :shock: :o
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Re: drag, twist, and transonic flight.

Post by TGC » Fri Apr 23, 2021 6:27 pm

Kenny, in the photos of the recovered bullets the imprints of the rifling is visible. I am curious about the rings visible around the bullets, are they from the grease groove nasa bullet? Tim.

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Re: drag, twist, and transonic flight.

Post by mdeland » Fri Apr 23, 2021 6:32 pm

Interesting how the nose tracks with the trajectory path rather than staying parallel with the initial path.

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Re: drag, twist, and transonic flight.

Post by mdeland » Fri Apr 23, 2021 6:39 pm

HG, that's like equivalent to some hand gun rounds at the muzzle with twice the mass! It certainly would "hole your tunic" if you were in it's path! :lol:

mdeland
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Re: drag, twist, and transonic flight.

Post by mdeland » Fri Apr 23, 2021 6:48 pm

I was thinking of the Webly revolver round !

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Re: drag, twist, and transonic flight.

Post by bruce m » Fri Apr 23, 2021 6:57 pm

mdeland wrote:
Fri Apr 23, 2021 6:32 pm
Interesting how the nose tracks with the trajectory path rather than staying parallel with the initial path.
mike,
you make the point of the original post.
in fact this bullet has a stability of well over the accepted optimum of 1.5 at 2.75, yet still obviously traces.
it will of course be a little nose high to the trajectory curve.
when zeroed at 1760 yds it will have a drop of about 25.6 moa from 1700 yds to 1800 yds.
given that 1 degree is 60 minutes, this is less than 1/2 a degree.
that is for a straight line, while the trajectory curve is more parabolic so would in fact be a little steeper at point of impact.
bruce.
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