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need a bullet drop for this load...!
Posted by BRWNBR on Apr 26 2006
i'm shooting a .416 rem with 350 barnes XXX BC of .521 @ 2525 FPS can anyone give me my drop at 500 yards with a 200 yard zero?
more trajectories
Posted by
George on Apr 30 2006
Brwnbr,
Like the others, I think the advertised BCs for bullets may be a bit
optimistic- so a big piece of paper at the range will tell the story. I did
do a little more playing on the ballistics calculator including using a
completely different calculator for comparison. After altering a couple of
variables, and for a reality check I dropped the BC by .1. The Norma program
with a couple of tweaked variables shows very little difference between a
.521 BC and a .421 BC. with something like 50-60" +/- inch drop below sight
line at 500 yards. Interesting though, a completely different calculator was
less optimistic on the trajectory, given the same parameters for bullets
with .521-.421 BCs- showing a 70-80" +/- drop at 500. Go figure?
On the other side of the coin though just looking at the
trajectories/ballistics, that round looks really good to a bit over 300 yds-
probably near or exceeding a max practical hunting/shooting range
anyway.
BC optimism vs reality
Posted by
Rick Smith on Apr 27 2006
BRWNBR,
I hope you have a place to shoot that far so you can verify that BC
figure. It is my feeling (and it's ONLY a feeling) that Barnes posted BC
figures for their TSX bullets are a bit optimistic. I believe the grooves in
the shank create wind resistance (drag) that will adversely affect bullet
drop at long range. I have no evidence to support this theory and would like
to see if someone can poke holes in it or show that it holds water (or
vodka, if you prefer). Let us know what you are able to learn.
Good Shooting, Rick
drop at 500
Posted by
George on Apr 27 2006
Well, I have absolutely no experience with that combination. However
according to Norma's calculations..... BC=521, 1.5" sight height above bore
line, MV= 2525, 200 yd zero... the drop at 500 yds should be about 38" +/-.
500 yard drop
Posted by
7STW on Apr 27 2006
Without exception,Barnes and virtually every other bullet manufacturer
overstate ballistic coefficients.In fact, the ONLY way to know the real BC
is to fire a round over two chronos and measure the time of flight.
Rick Jamison popularized this approach in numerous articles.He found that
most BCs were way overstated...sometimes by up to 40%.Barnes was one of the
worst offenders.
I asked Randy Barnes about this at SCI once.He smiled and said" well, we
have to stay competitive!"
Additionally, true BC will vary based on MV (it's not a constant factor at
all speeds)...altitude...and atmospheric conditions.Those factors alone
could easily cause a miss at 500 yards on anything smaller than a Jumbo.
Bottom line:If you can get a perfect zero at 200...if your group size is
small enough to not cause major fluctuations in mid point trajectory...and
if you can find a measured 500 yard shooting area, you will know the drop of
that particular load and bullet.
From there, you can go to established drop tables and interpolate the
approximate BC.I'll eat one of the 350Xs without ketchup if it even
approximates .531.
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