Gain Twist Yay or Nay

Thanks for the education, I'd never heard of this term before either.

All I know about 6.5x55 and 7x57 is the twist rate isn't the big deal, its having a long throat. Those 160gr 6.5s and 175gr 7mm bullets are what made the stuff of legend in a hundred years of safari literature. Make sure they like to shoot the big-uns!
 
From a purely academic point of view my observations are as follows - if you try to force a bullet down a barrel with a tight twist - just as an extreme example think of 1:100 - in the same way a common screw resists being pulled out of a piece of wood - the bullet will resist going down an extremely tight twist barrel and pressures will go extremely high - and the jacket might tear - just like in a barrel that is too small or screw tearing out of wood. The screw will be easier to pull out of the wood if the twist is 1:2 whereas if it is 1:200 it will tear the wood before it comes out. Theoretically, a progressive twist barrel will get the bullet spinning before it tightens up to a tighter and tighter twist. The lower twist at the beginning would allow lower initial pressures, and as the burning chamber expands with the bullet going down the barrel the lower pressure remains stable or decreases as the twist rate increases.

I think the progressive twist makes theoretical sense if you are trying to either keep pressures lower with a very tight final twist; and/or keep a bullet jacket tearing with a very tight final twist.
 
Hornady has an extremely good podcast about gain twist barrels. Gain twist isn't something particularly new, and it's often used on auto cannons (bore diameter typically above .50 cal) to avoid stripping driving bands and so on.

Highly suggest watching the podcast, it covers loads of technical information as it pertains to gain twist barrels.
 
You must log in or register to reply here.

Members online

... and 1095 more.
Total: 59,832 (members: 1,145, guests: 58,687)

Forum statistics

Threads
65,326
Messages
1,441,473
Members
135,599
Latest member
EvieChurch
 

 

 

Proudly sponsored by

Latest posts

Latest profile posts

crossfire3006
crossfire3006 wrote on Hornedfrogbbq's profile.
An excellent AH member right here! I had a fantastic transaction with Hornedfrogbbq (I was the seller). His communication was first rate, payment was extremely fast, and I would have absolutely no reservations at all dealing with him again. Thank you, F!
•••
HENRY GRIFFITHS SAFARIS
HENRY GRIFFITHS SAFARIS
Here we are, the last day of the show in Denver, it's been a good show but expecting a quiet day today. I will be back for-sure to do this show next year and maybe also do the one in Sacramento California.

On Monday I will be hitting the road driving from Denver and eventually make it down to Atlanta for the flight home.

its going to be a good year!
•••
C
CraigV wrote on Rem280's profile.
Hi Rem280, Saw your post on getting selected for Idaho Elk. Do you have a zone(s) selected? I live in N Idaho, might be able to offer some ideas.

Cheers,

Craig
•••
G
ghay wrote on Konrad.inc's profile.
Do you still have the Ruger 9.3x62?
•••
HENRY GRIFFITHS SAFARIS
HENRY GRIFFITHS SAFARIS
I have made it to Atlanta this morning, few other outfitters on same flight and our luggage never came trough, looks like mine will go via France to Denver hope it gets there before the ISE show starts on the 8th TOMORROW!



flying to Denver in an hour! is it to early to hit the bar:)
•••

Share this page

 
Top