Has anyone ever heard of this, what I gather is it is a .416 Rigby necked down to .308, a guy named Vint Knechtges was getting 3900fps with 250gr Soft points using 85grs of H4831. Does anybody have one? or ever heard of it?

Rock

I have spoken with Vint on several occasions since his move to Texas. He says that the muzzle blast is pretty significant, but with his muzzle brake, the recoil is well below what is expected.
The case capacity is 123.2 grains of water, full to the case mouth and it has a 45� shoulder. I have the dimensions and a drawing, if you'd like to have a copy. Unfortunately, I have never owned or shot one.
Regards,
HockeyPuck

They say it's pressure-heat and not speed that burns out throats. This would be a great one to test that theory.
Load it "down" to around 3600 and loose a hundred rounds or so.

best way is perhaps to use a 30/338 Lapua or a 30/338 Lapua imp , 338 Lapua case are far stronger than the low pressure rigby draw and more easy to neck down , water capacity between 30/338 imp and 30 Cody are probably close even if 416 case is a bit longer

if you need more 30 Viper is available ( 30/505 Gibbs )

good shooting

DAN TEC

Rock,
My smith Dave Caboth (907-376-5261) has a 30 Cody Express reamer he might sell. I wanted to use 338 Lapua brass, so I had Dave Kiff make me an Improved version with a 40 degree shoulder blown out to .570" at the shoulder... with a .405" long neck to quelch the throat errosion.

3900 with a 250gr? Who makes a 250gr 30 caliber bullet? I know Sierra makes a 240 SMK. I don't see how it would ever get to 3900, anyone know?

Gentlemen,

You might like to have a look at our Reloading Pages, and see our data for some of the 30 caliber wildcats we have shot.

Especially the 300 Phoenix and the 300 Pegasus.

..yeah...

it's called a 30-378, if you add a belt....

jeffe

I think they meant a 150 gr bullet at about
3900. But that still is a little high pressure when info is put in the formula.

FORMULA FOR RIFLE VELOCITY THAT WORKS;

VELOCITY EQUALS 8000 TIMES SQUARE
ROOT OF ALL OF FOLLOWING-----------
POWDER WT TIMES EXP/RATIO MULTIPLIER
DIVIDED BY BULLET WT & 1/3 POWDER WT.

IE--VEL = 8000 X SQ ROOT OF ALL BELOW

______________________________
!.../
!../POWDER WT X EXP/RATIO MULTIPLIER
! /_________________________________
!/
/ BULLET WT + 1/3 POWDER WT

POWDER AND BULLET WT IN GRAINS.

THE 8000 CONSTANT IS FOR 45,000 PSI-
IMR POWDER.

USE 8300 FOR 50K IMR POWDER AND 45K
DOUBLE-BASE POWDER .

USE 8600 FOR 55K IMR POWDER AND 50 K
DOUBLE-BASE POWDER .

ADD 150 TO CONSTANT FOR CHAMBER SAME
DIAMETER AS BORE .

TO GET EXPANSION RATIO YOU TAKE TOTAL

VOLUME OF THE CHAMBER AND BARREL, AND

DIVIDE BY VOLUME OF THE CHAMBER .

HERE IS CHART OF THE EXPANSION RATIO EFFECT

WHICH SAVES A LOT OF COMPLICATED MATH,

MAKING ABOVE FORMULA EASIER. THE MULTIPLIER

IS ONE MINUS THE INVERSE OF THE 1/4 ROOT OF

THE EXPANSION RATIO.

EXPANSION RATIO.........MULTIPLIER

16 TO 1------------------.500

14.5 TO 1-----------------.488

13 TO 1-------------------.474

11.7 TO 1-------------------.460

10.5 TO 1--------------------.445

9.3 TO 1---------------------.430

8.3 TO 1----------------------.412

7.4 TO 1----------------------.394

6.5 TO I-----------------------.375

5.75 TO 1-----------------------.355

5.0 TO 1------------------------.333

FOR EXPANSION RATIOS BETWEEN THOSE ON
CHART YOU CAN INTERPOLATE TO GET MULTIPLIER.
THE FORMULA SHOULD BE WITHIN 2% FOR LOADS
AT OR ABOVE 90% LOAD DENSITY.
OF COURSE THERE ARE SLOW AND FAST BARRELS.
THE FORMULA DEPICTION I USED IS BEST I
COULD GET ON HERE.ED

--------------------
Ed Hubel

To show how the formula works--Using top example
of powder wt and bullet wt---With this case the
expansion ratio, will be low, so the multiplier
is .333 or lower..------So you take 85 gr powder
times .333 = 28 and divide that by 250 gr bullet
wt plus 1/3 powder wt 28 = 278. So 28 divided
by 278 is about1/10 as fraction.Easiest to do it
as a fraction. Square root of 1/10 is 1 over
3.2. Assuming 55-60,000psi load, you would times
the constant 8600 by 1 over 3.2, which is the same as dividing it by 3.2 = 3000 fps.For a 250
gr bullet.So the fellow he mentioned getting
the 3900 was about 2900.Just a wrong report or
misprint.To get the 3000 the expansion ratio would have to be figured on about 32 in barrel or longer with this case capacity to bore size ratio.This formula is easy as I have sq root
chart and can figure a load in 20 seconds.With
pen and paper.Great for wildcatting and experimenting.Ed.