In assessing the .224 Clark I’m forced to quote G1 values; the industry is
somewhat reticent to adopt G7s.  Using Hornady’s online trajectory tool I
compared the Clark to other flat shooting rounds:
Input conditions:
  • Zero = 200 yards
  • Temperature = 68 F
  • Humidity = 10%
  • Pressure = 25 hg
  • Wind angle = 90 degrees
  • Wind speed = 5 mph
Cartridge
Bullet Wt
G1 BC
Velocity
300
500
700
1,000
Vel @ 1,000
.220 Swift
55 grs
0.271
3,805
-4.7
-34.8
-92.5
-309.0
1,054
.224 Clark
90 grs
0.551
3,600
-4.1
-24.2
-63.7
-171.1
1,940
.240 Weatherby
100 grs
0.375
3,134
-6.4
-38.7
-107.3
-323.0
1,171
7mm STW
150 grs
0.519
3,267
-5.7
-30.7
-81.1
-222.2
1,642
.300 Ultra Mag
180 grs
0.501
3,265
-5.3
-31.2
-82.8
-228.7
1,592
.50 BMG
750 grs
1.095
2,800
-6.6
-36.2
-90.1
-223.9
2,027
Cartridge
Bullet Wt
G1 BC
Velocity
300
500
700
1,000
% Vel Drop
.220 Swift
55 grs
0.271
3,805
4.1
12.6
28.3
74.0
72%
.224 Clark
90 grs
0.551
3,600
2.0
5.8
12.1
27.3
46%
.240 Weatherby
100 grs
0.375
3,134
3.7
11.1
24.1
57.2
63%
7mm STW
150 grs
0.519
3,267
2.4
7.1
14.8
33.7
50%
.300 Ultra Mag
180 grs
0.501
3,265
2.5
7.4
15.5
35.5
51%
.50 BMG
750 grs
1.095
2,800
2.1
3.8
7.8
16.6
28%
Even though the Clark's reputation at distance is stellar, these results were
eye-opening.  At best I figured it could hang with STWs and Ultra Mags, not
eclipse them.  The Berger VLD did most of the lifting though.  Its high SD and
secant 15 ogive returns a jet-like BC.  Coupled with Ken Clark's old over-bore
wildcat and we have enough push to get the ultimate in flat.

Before we wrap-up I want to mention a couple of things.  Ballistic coefficients
are not absolutes.  Atmospheric pressure, temperature, humidity, and
altitude can alter a bullet’s BC.  Secondly, G7 BCs are not immune to
velocity.  They do change as speeds alter, just not as much as a G1
coefficient.   Last but not least, sectional density (SD) is a critical variable
when it comes to trajectory:

BC = SD/i = M/(i x d^2)  
The form factor “i” = (Cb/Cg)
Cb = drag coefficient of the bullet
Cg = drag coefficient of G1 (~0.5191)
M = mass of bullet
d = diameter of bullet

If you want to defeat wind, the above derivation is telling.  Create a low-drag
projectile of high mass relative to its diameter.  Big ballistic coefficients soon
follow.  The last ingredient to add is velocity!!!
So it goes fast and shoots flat.  But is it accurate?  Retumbo and US869
returned tight and consistent little clusters with the 90 gr Berger.  A slight
edge to the 869 on group size and velocity, but the Clark and Retumbo mix
well.  Both loads gave 3/4 MOAs or less, the tightest being 0.408":
Like so many of the wildcats we build, the Clark fills a specialized role.  To
truly stretch its legs you need to stretch the target, literally.  Inside 400
yards and you might as well grab a Swift or large 6mm.  Otherwise it's like
driving a Ferrari and never clutching high gear.  Of course loads can be
tailored, or de-tuned, to increase longevity for shorter ranges.  Its
flexibility is easily over-looked.  But going that route leaves you with a very
high dollar one-off rifle.  I don't know if mine will ever see 1,000 yards but
I sure hope it does.  Regardless, I'm pleased with our new small bore
missile.  This .224 is fast, accurate, recoils little, and acts like a
range-finder when zeroed at 400 yards.

To date mine has seen 200 rounds. I'll post updates as it approaches 500,
then 1,000.

Please direct questions and comments to lee@singleactions.com.