Is the 1:16 twist of the CZ 550 Rigby barrel enough to stabilize the Barnes 400 TSX and the CEB 400 solid?

It appears that the 1:16 twist is marginal at best for these bullets, and that using (for example) a
Barnes 350 TSX/ 350 solid combo would provide better stability, higher velocities and less recoil
with little (if any) loss of performance. It seems that with the advent of the high performance 350/ 370 grain
bullets that the 400gr bullets are sort of "old school " in the Rigby.

In Michael's epic thread he thought that the 1:16 twist was not enough and the 350gr bullet range was the way to go.

Thanks all!

I would call CEB. They can get you all the info needed on their bullets.

on the specific question, IDK.. however, I have never had any trouble with barnes bullets, including solids, in the rigby/cz, but haven't tried the specific bullet in question

I have e-mailed CEB and Barnes CS ; I will post
their replies

CIP twist for the .416 Rigby is 1:420mm = 1:16.54" twist.
From the days of cup&core, not good with long monometals, aye.
The old CZ 550 Magnums used that 1:16.5" twist, may have done differently lately, I do not know if they ever went to a 1:14" twist like others.
George Hoffman preferred 1:12" twist for the .416 Hoffman after all his experience.


Try this McGowen twist calculator on the CEB if you have the bullet velocity, length, and know the monometal, brass or copper:

http://mcgowenbarrel.com/twist2/

Barnes TSX .416/400-gr, copper, is 1.590" long.
At 2400 fps MV 1:16.9" twist does it, and they advise rounding down to the nearest half inch,
so: 1:16.5" is slowest barrel twist to consider.

That is for stability in air.
Might tumble too easily in game,
just like the Barnes .458/500-gr TSX has been shown to be stable in air but cannot stay on course after impact.
With 1.663" length for the .458/500-gr TSX,
1:18" twist is good for 2100 fps and faster MV,
1:14" twist is more than enough, makes for superb accuracy, and reliable tumbling on impact with anything much denser than air !
450-gr and lighter are good in the .458-caliber TSX,
in same ways you reason that the .416/350-gr TSX is better.

Rip ...

Thanks RIP!

I am most interested in the CEB 416 350/ 400gr solids, just threw the TSX into the mix for the heck of it.

CEB 416 350 solid 1.331" 19.7 twist, CEB 416 400 solid 1.949" 17.5" twist using the McGowen twist calculator. On paper the 1:16 appears OK.

RIP makes a good point about stability in air vs animals, however there are some different performance requirements for
a TSX-type expanding bullet vs a flat point solid. Michael said in his thread that the CEB noncoms and solids
performed about 30-35% better in animals vs the test media for penetration tests.

Pics from the B&M website

https://www.b-mriflesandcartri...0623.jpg?u=232646016

https://www.b-mriflesandcartri...680.jpg?u=2252246054

I loaded some 350 and 400gr CEB solids in my 416 Rigby with 90gr H4350, don't know the velocity as the weather has been too bad to get out to chronograph them.

At 25-30 yards the bullet holes in the targets were nice and sharp and showed no evidence of instability, both were stupid accurate and the iron sights were
spot on.

Given the results Michael obtained the 350 CEB solids appear to be the way forward; less recoil, more velocity and little (if any) loss of performance.

Got a response back from Nikki Hampton Croasmun
at Cutting Edge, said it was OK since the stability
factor was greater than 2.0

I have no idea what a 2.0 stability factor is
or how it is calculated

I asked her how it is calculated

Perhaps the number provided by the McGowen
plugin on their website is called the stability
factor

Stay tuned for further info

Searching the interwebs, the formula for calculating
the stability factor is very complex:

https://arxiv.org/ftp/arxiv/papers/1410/1410.5340.pdf

Maff is hard, yo!

Many bullet makers have online plugin twist calculators:

https://bisonballistics.com/calculators/stability

This particular one indicates that both CEB solids
are overstabilized in the 1:16 CZ Rigby

CEB bullets uses the JBM stability factor plugin
on the JBM website:

https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi