Greetings

First of all I like the new shape of AR.
Well done!

As to bullets...I`m doing ballistic charts
for various big bore cartridges in various
loadings(including those from AR reload pages)
Alas,I can`t complete the chart for .577 T-rex
because despite my searches,finding Ballistic
Coefficients for some .585 bullets seems to be
on the brink of impossibility.Those bullets are:
-750grs A2 Dead Tough
-750grs A2 Lion load
-750grs Naval Ordnance
-900grs Woodleigh

I tried reloadbench bullet database as well as
Woodleigh website(btw.Woodleigh don`t even list
.585 900-grainers in their on-line catalog I thought they were "special order" not "top secret" bullets )
and didn`t find them.Can anyone help?

TIA

On the 750gr A2 bullets in the T-Rex, the factory ballistics table shows them moving at 2460 from the muzzle, then 2197, 1950, 1723, 1516 at 100, 200, 300, and 400 yards. I'm sure someone here has a formula to work out the BC based on this data. Don't know if this helps...just a thought.

Why would the BC matter in a rifle designed to shoot 50 yards?

Just asking.

Darth, I got woodleigh to design the 900 grainers back in about 2001. There were only a few hundred made and since then woodleigh has said they are not interested in making any more.

Not sure what the BC is of this bullet.
They are 1.4" long. The cannelure is about .76" up the shank.After which they have starting a 'gentle roundish sort of ogive'(lesser known engineering term ) which ends in a 38 cal flatpoint.

Also beware, the BC's listed on Woodleighs site do not seem accurate since a lot of its big nitro softpoints are attributed figures in the mid .4's, which to me seems spitzer territory.

Karl.

Here is a chart to help determine BCs based on
velocity lost per each 100 yds.Take average of
loss for first 300 yd spaces.

Velocity left--------BC
after 100 yds
96%----------------.840
95%----------------.656
94%----------------.536
93%----------------.461
92%----------------.410
91%----------------.373
90%----------------.340
89%----------------.314
88%----------------.290
87%----------------.270
86%----------------.252
85%----------------.238
84%----------------.223
83%----------------.208
82%----------------.197
81%----------------.182
80%----------------.168

Big heavy long bullets can get high BCs with blunter points, compared to lighter
smaller calibers, with more steamlined shape,
because big weight makes long bullets.Ed.

True Ed. But I think woodeigh may take it a bit far. Their 500nitro roundnose is given a BC of .47 or so which is similar to Barnes' figures for their 450gn X-bullet in 458.


Karl.

Karl- Your right the .470 seems high for a
500 cal roundnose bullet unless it weighed
800 gr or more. Another good aid in determining
BCs is the Hutton Rifle Ranch BC calculater, that coame with the Powley Computer.It has a chart with different bullet nose shapes,called form factor that you compare your bullet to, and then you figure sectional density when you
figure the caliber and weight info.Then you
do the math with SD and Form factor, and you have the BC.Ed.

I have often though woodleigh are a little optimistic with there BC's

Me too PC and now Ed has confirmed it.
I usually very roughly give them a BC around the low point threes and cut off about 250-300 fps per 100 yards till 2000fps. This is working back from velocity calculations with 700 nitro/nyati/460/375 etc starting at 2600fps.

It seems to fit in with printed ballistic tables and Ed's percentages above.

Karl.

Hi,
If you want top quality Core Bonded bullets in the shape,weight and caliber you want -contact Ken Stewart of "Stewart Core Bonded Custom Bullets" in South Africa.

His bullets has a tremendous reputation among PH like Harry Selby, Ganyana and others!

Ken doesn't have any homepage -but you can fax him at: +27 15 2899401.

/Husky

Hi!
Sorry for the delay in responding.
Little problems with my Internet connection.

gringo pistolero:
"I`m sure someone has a formula to work out the
BC based on this data.
"...just a thought "

Well...I have I`ve checked the data with
Joe`s ballistic calculator www.realguns.com
The BC is .316

500grains:
"Why would the BC matter in a rifle designed
to shoot at 50 yards?"

Hmm,in my case it`s pure curiosity.I know the BC
is much more important when you intend to shoot
and HIT something at 300+ yards.Still,I like
to compare various cartridges,I like to know how
bullets behave in flight and when they connect.
For me making those ballistic charts is both
fun and opportunity to learn somethin new.
I`m a gunnut but OTOH aren`t we all gunnuts?

hubel458:
"Here is a chart to help determine BCs....."
I didn`t know this method before. Thank you for
sharing it.

Karl,Hubel,PC

Yep!I find Woodleighs` BCs a bit optimistic too
but that`s what we have.

Thanks for the replies.

Good shooting
------------------------------------------------

Darth,

I did not shoot anything at a greater distance than 25 yards with my .585 nyati, so I suppose even sighting it in at 100 yards was wasted effort.