Also remember that bigger cartridges can stabilize longer bigger bullets like the EOL with less twist that smaller cartridges. The 6.5 creedmoor and PRC need the 1/8 twist and if they are cursed with a 22" barrel may need a 1/7.5. However, stability is not the product of twist alone but of twist combined with speed. These factors give you faster or slower rpms (spin) which gives you more stability.

You have to shoot them to find out.

A 308 needs a 1/9 or faster twist barrel to shoot 190-200+ class of bullet (or so I've been told) but my brother's 30-06 shoots 190g with a 1/12 twist just fine.

I suggest that if a 6.5 cm needs a 1/8 twist shooting 156 EOL @2700 that's

162,000 ft/pminute

1,944,000 in/pm

÷8= 243,000 rpm

Now let's say a 264winmag can shoot a

**156 EOL @3200**....that's:

192,000 ft/pmin

2,304,000 in/pm

... So if the 156 is stable out of the cm @259,200rpm then we can divide 2,304,000(inches per minute) by 243,000rpm to find the minimum twist for the 264 winmag to shoot the 156...

Which is: 9.481" (inches) or basically

**1:9.5 twist**...

SO

YOU CAN SHOOT THE BERGER 156 EOL OUT OF A

**1:9 TWIST **BARREL AS LONG AS ITS A 264 WINCHESTER MAGNUM