Thread: rifling twist what are the effects?

im not sure if i have this in the right forum, but for example tikka 223 seem to have 1 full twist per 8 inch and 1 full twist per 12 inch options ( if i understand this correctly? ) so the 1/8 will make the bullet spin more correct? what are the pros and cons? does the fact the projectile has to rotate more use more energy thus slowing the projectile down? but also improve accuracy? and so in 223 cal for 100m shot what would be an ideal twist rate to go for?

1:8 will spin the projectile faster and therefore stabilise heavier projectiles

Originally Posted by MSL

1:8 will spin the projectile faster and therefore stabilise heavier projectiles

yes but there must be some down side of having more twist? other wise wouldnt all rifles have more twist than what they do ? im just trying to understand all the different perspectives before i buy the wrong thing lol

Originally Posted by birch

yes but there must be some down side of having more twist? other wise wouldnt all rifles have more twist than what they do ? im just trying to understand all the different perspectives before i buy the wrong thing lol

Different twists have different effects on projectiles. I will stick to 223 as an example as that is what I am familiar with. the slower twists (like 1:12) will stabilise lighter projectiles like the 35 and 40gr varmint projectiles but will not put enough spin onto heavier projectiles to get ideal accuracy. A faster spin (like the 1:7) will stabilise the heavier projectiles like the 69 and 75gr which are more suited to animals that a lighter bullet may not drop effectively (or hold more energy further down range)

As I understand it, this is in part due to the speed with which the bullet accelerates down the barrel from stationary in chamber. As expected the lighter bullets accelerate much quicker and the heavier bullets take a little longer.

As you increase the rifling rate then as the faster bullets go through a faster twist (take it even further and say 1:4) then these rifling lines are now going to be too fast to have any effect at spinning and will behave more like lateral grooves shaving the bullet. (Think of how a cattle stop would affect a log dragged behind a car)

Slower (heavier) projectile need a faster twist, faster (lighter) projectile needs a slower twist.

You can shoot heavier bullets through the 1:12 twist but accuracy wont be ideal My rig is a 1:12 and I get 3-5 shots touching at 100m using 35gr -45gr projectiles if I do my part but with anything over 55gr those groups go out to 2 or 3 inches at the same range. This is ideal if you are shooting rabbits at 200 to 300 metres or more. But those light projectiles are not good on goats or deer.

If I wanted to use it in goats or deer the 1:7 twist and using a 60-75gr projectile would be better (more energy on impact) .

What are you wanting to do with the 223?

Originally Posted by birch

yes but there must be some down side of having more twist? other wise wouldnt all rifles have more twist than what they do ? im just trying to understand all the different perspectives before i buy the wrong thing lol

As I understand you are correct. Faster spin rate will add friction, which in turn will reduce MV. Neither twist will be more or less accurate with the right weight-for-twist bullet.
This becomes a two edged sword for the shooter. I want my bullet to go as flat as I can but with as little wind drift as possible.
Flat and fast are hand in glove but wind drift and bullet weight are also proportional, heavy for cal pill = less wind drift.
My suggestion, go fast twist. Bullet drop is consistent and an easier factor to compensate for. But in a 223 @ 100m? Probably not much in it. Far better investing in shooting practice and better optics.
My last 1:12 223 shot 50g BT to 400y on still days when out hare busting. Any significant wind and that came down to <200y

With a 223 Tikka there is only one to get, the 1-8.

You can't push the light projectiles fast enough to upset them with the extra twist.

Mr Litz says faster twist = higher BC & the velocity loss from a faster twist is generally inside the normal ES except in special cases, ie really slow to really fast twist.

Fast twist can have some dramatic effects - seen that with a fast twist 223 barrel fitted to a 22-250 and projectiles vapourising part way to the target.

Also fast twist will cause higher pressures and may be not able to reach desired fps b4 over pressure becomes an issue. Been watching a mate trying to get 7mm 183 gr SMKs with long bearing surfaces perform in a fast twist 284W. Ran into pressure problems b4 reaching a desired velocity. Firing 180 gr Scenars and no problem with getting fps and accuracy with acceptable pressure. Firing the same SMKs in a SAUM no problem. Fitted a 1:9 barrel to the 284W and now reaching good velocity (in the node) with the SMKs with no pressure issues. Improved velocity has optimised the BC.

A balancing act of trade offs.

Twist Rate Stability Calculator | Berger Bullets

What do you plan on doing with it?

If you want to shoot heavy (read long when talking twist) bullets for long range then go 1:8 or 1:7.

If you want to explode varmints with light fast little laser beams then 1:12 is better.

Sent from my SM-G360G using Tapatalk

ok im basicly looking for a 223 for shooting wallabys at 100m using factory 50 or 55 grain ammo ( one day i will get into hand loading but that day is not now ) but also want to use it for a bit of target shooting- but probably not so much that i would need a heavy barrel?

Originally Posted by birch

ok im basicly looking for a 223 for shooting wallabys at 100m using factory 50 or 55 grain ammo ( one day i will get into hand loading but that day is not now ) but also want to use it for a bit of target shooting- but probably not so much that i would need a heavy barrel?

Heavy barrels help if you are shooting long strings of rounds. A stonger barrel will take longer to heat up (and to cool) and will bend less as it heats.

On Wallaby's I would not go below 50gr so the 1:7 would be the better option allowing you to use factory ammo right up to the 75gr mentioned as well. All should work well enough. Bunnies at long range do not need that much weight so the lighter bullet travels much faster allowing for lighter trajectories. If you were looking to go varminting then I would suggest the 1:12 and go for the much lighter projectiles (or get a 204 ruger instead)

Originally Posted by timattalon

On Wallaby's I would not go below 50gr so the 1:7 would be the better option

40gr Nosler BT is lethal on wallabies so no need to stay above 50gr, I've seen them shoot well from 1:12 and 1:9 twist.

Originally Posted by birch

ok im basicly looking for a 223 for shooting wallabys at 100m using factory 50 or 55 grain ammo ( one day i will get into hand loading but that day is not now ) but also want to use it for a bit of target shooting- but probably not so much that i would need a heavy barrel?

I have had .223's with twists from 1:12" to 1:8", the 12" will handle bullets up to 60 grains the 8" up to 80 grain SMK's I used a 1:8" .223 to shoot NRA Fullbore from 300-1000 yards
if you want to do NZDA target shooting which is 100 and 200 metres 52-53 grain bullets are fine if long range the bullets start at 69 gr SMK and need a 1:8" twist, See what is available
in of the shelf rifles, a standard Tikka T3 is a good rifle to start with, Hornady load 50 and 55 grain GMX in .223 if you want some Hi Tech bullets for deer

wow this is not as clear cut as i thought, maybe because im thinking of 50-55 grain im kinda in the middle

A heavier twist barrel will give you more options.
You can try heavier projectiles in a heavier barrel which you can't do in a lighter twist barrel.

I have a Savage Model 12 .223 which my son & I began FTR target shooting with. It has a 26" 1:7 twist barrel.
Fitted a 20 MOA rail and a scope and went target shooting. No other modifications.

We've always used 80gr A-Max with it, with 24.7gr 2208 in Norma cases.
Punches paper out to 1000 yards. Suffers in heavy winds beyond 800 yards. Competitive with 308s in lighter winds.
A pleasure to shoot. Cheap to shoot.