Actual BC for 6.5 Lapua 139gr Scenar

[Rootshot]

The advertised BC for the 6.5mm 139gr Lapua Scenar bullets is .615. Has anyone verified this figure?

Berger is accused of inflating BCs, Sierra has a reputation for being Spot-on, but I haven't heard about Lapua.

--Rootshot

 

[mikecr]

Measuring mine & running the numbers, I would say .570G1BC @3Kfps, ICAO, for the 139.
.580 for 142SMK
.595 for 142Wilcat ULD
.610 for 140Berger vld.
.618 for 147CR
.638 for 140JLK

But nothing field verified. Just calculated.

 

[sparker]

In regard to inflating BC values, I must protest. The values that Berger initially posted were based upon calculations performed by Bill Davis. Those values fall well within 110% of the "actual values".I have known Walt and Eunice Berger for years. I can assure you that there has never been any attempt at deception. Berger simply supplied the best data that was available. If you have visited the Berger web pages recently, you might have noticed that many of the BC values have been updated. Eric Stecker, who is running the show now is an honorable businessman who is steadfast in his commitment to produce the best bullets available. Eric listens carefully to his customers and makes well informed decisions about bullet making.

Try to get Sierra to listen to you about changing bearing length or meplat diameters or ogive shapes. Sierra's values are accurate because they are measured. Imagine Joe,shoots once a month at a ground squirrel) Smith who owns a $99 chronograph with one foot screen spacing gets his load velocity of three fired rounds, dials in his $99.99 super duper varmint scope and uses the most optimistic trajectory numbers he can find. What would you know, he misses that ground squirrel at 500 yds with the first shot. Joe now thinks that the BC value must be wrong.

 

[sparker]

Continued.

I shot a 600 yd prone match last week. I used Berger 105s traveling at 3050 fps. Using a BC of .541 in Art Peja's program, the calculations predicted a 9.87 minute drop from my 200 yd zero. I came up 10 minutes and the first shot was high in the 9 ring. I dialed down 3 clicks and shot a close 10. I ended up with 9 minutes on for elevation for that 20 shot string. Obviously, for that program and those conditions, the BC value of .541 was a little low. Well, the original value for the 105 vld was .565. I believe the difference between the value that I experienced and the .565 value is less than 2%.

By the way, I won that match.

Scott Parker

Bakersfield CA

 

[rhino]

139 bc is very similar to the 142 SMK, as I don't click up much or down. They pretty much shoot to similar point of impact at 1k.

140 amax shot benath the target and the 140 bergers over the target with 139/142 1000 yard zeros.

Never shot JLKS

RHINOUT!

 

[Hayes]

Gents,

Below is a list of 6.5 bullets that I tested for B.C. in July 05 at 300 yards using two Oehler 35p chronograph's here in Phoenix.
Temp's were 85-90 degrees. I used Sierra's program to determine the numbers for ea. bullet . The average speed was used over a ten shot sequence at the muzzle and at the target.

107 gr. Sierra .445

108 Lapua .456

120 cauterucio vld .527

123 Lapua .520

130 Norma .543

131 cauterucio .533 at 200 and .550 at 300yards.


140 Berger .627 at 300 and .634 at 200.


I recently tested 139 Lapua's at 300 yards in about the same conditions at 85 degrees . B.C. .595 .

I USED A KREIGER .260 8 TWIST FOR ALL OF THE ABOVE EXCEPT THE 139 WHICH WAS TESTED WITH A KREIGER 8 TWIST IN 6.5XC .

The Berger AND the Norma were identical to their claimed B.C'S.

The Sierra 107 exceeded the claimed B.C .

The Lapua's were on avg. .020 lower than claimed.

I have additional info regarding the specific's i.e., humidity, pressure, starts and stops for velocities and some numbers that Medesha and Tompkins came up with at 600 yards for some 6mm bullets if interested.

Phil Hayes

 

[Mark Walker in TX]

Gents,

Below is a list of 6.5 bullets that I tested...

Phil,

Great info - thanks for posting!!!!!

Mark Walker

 

[JER]

The Lapua's were on avg. .200 lower than claimed.

Certainly you mean .020 lower......

 

[rhino]

Like I said about the same as a 142 SMK. Just the quality is much better IMHO!

RHINOUT!

 

[JER]

Like I said about the same as a 142 SMK. Just the quality is much better IMHO!

RHINOUT!

+1

And as cheap or cheaper than Sierra if you get them from Graf's.