.243 Twist Ratios

[Norty_Country_Bloke]

I'm interested in a .243 Winchester as a varminting rifle, with the ability to handload some heavier stuff for pigs and the two smaller deer species (.243 is legal, correct?)

I want to shoot a pill on the lighter side of the spectrum. 55gr, etc. Now what twist ratio would be properly suited for a 55gr, and how far up the weight range could I go before I run into problems stabilizing the bullet.

This is important to me because I value the .243 over the .223 for the performance with heavier projectiles, while still handling the 55gr just as well.

Thanks blokes, cheers.

[Apollo]

The normal twist rate for a .243W is 1:10" Twist.

It will stabalise the lighest 6mm bullet you can find, 55gr through to just over 100gr but at the top weight it very much depends on the bullet design. If they get a bit long it will not stabalise them.

I shoot 55gr Hornady V-Max through to 100gr Sierra GameKing in a .243W Tikka T3 Varmint 1:10" Twist 24" Barrel.

At each end of the scale I found that accuracy is not as perfect as mid range weight like 70-80gr. When I say accuracy at mid range weight I'm talking 0.5 MOA or better down to tiny groups with specialised target grade bullets and the best case / load development.

The .243W is very loud with a destinctive bark but gee, it makes an explosive mess of a Rabbit at 200m plus with a 55gr bullet. On the otherside with a 100gr Soft Point it is very destructive on larger creatures.

Have never shot Deer.

In my kit I have 55gr, 75gr and 100gr loaded usually and the sighting data for each depending on what I want to do I switch. For target shooting, well. 75gr to 90gr and the later are about to be tested 90gr Lapua Scenar (Moly) to see if they out do the 75gr I have found to be the most accurate.

There are a huge variety of 6mm bullets available but remember the .243W is a "barrel burner" so don't waste too much usage testing. Not as bad as the 22-250 but not too far behind.

[Norty_Country_Bloke]

A lot of worthwhile information in there. Thanks, Apollo!

[mausermate]

agree with Apollo and my Sako with a Maddco 22'' has a 1:10 and it loves 85gr Sierra Hollow points and doesn't mind 55grs but I rarely use them. I also have a 22/250 so use it if I want to go that low in projectile weight. When I put 100gr bullets in my 243 it goes to hell and sprays them all over particularly Nostler BT's. So I stick with the 85's and is excellent on everything from foxes to roo's, goats and pigs. Never tried it on Deer.

[Releb]

Sierra say the required twist for their longer bullets when they need something extra. Just a rough guide for you but I thought it was helpful to get an idea of things.

Look at the heavier end of their .243 pills list and they say:

85gr SPT - "...standard twist rates"
85gr HPBT - no mention
90gr FMJBT - no mention
95gr HPBT MATCH - "This bullet requires a 9" twist barrel."
100gr SPT - "...standard twist rates"
107gr HPBT MATCH - "This bullet requires a 1x7" to 1x8" twist barrel."

Not exact but gives you an idea of where the tipping point is and you're looking at something that's probably wrong.

Hope it helps.

[Oldbloke]

There is some good info here.

http://www.shilen.com/calibersAndTwists.html

[mausermate]

Sierra say the required twist for their longer bullets when they need something extra. Just a rough guide for you but I thought it was helpful to get an idea of things.

Look at the heavier end of their .243 pills list and they say:

85gr SPT - "...standard twist rates"
85gr HPBT - no mention
90gr FMJBT - no mention
95gr HPBT MATCH - "This bullet requires a 9" twist barrel."
100gr SPT - "...standard twist rates"
107gr HPBT MATCH - "This bullet requires a 1x7" to 1x8" twist barrel."

Not exact but gives you an idea of where the tipping point is and you're looking at something that's probably wrong.

Hope it helps.

As I have said before "this forum is awesome". I never tried a 100 gr SPT in my 1:10 243. Only used boat tails and never found the data to have reason for a change.

Really grateful, thanks heaps. I know what I'm doing Sunday

[Releb]

No worries mate.

Happy to help.

[bm777]

70gr Nosler (purple polymer tip), good all rounder and no trouble. If you go lighter, your muzzle velocity increases and so does the wear on your barrel. 243s are known barrel burners. Also depends on what you use the rifle, target/hunting and a bit of both..

I have a Ruger M77MkII with a standard flimsy factory 22" 1:10 barrel, which I have now replaced with a shilen varmint profile with 1:8 26". Now we're cooking with gas!

[Lorgar]

70gr Nosler (purple polymer tip), good all rounder and no trouble.

I was shooting the 80gr in my Ruger when I had it, 1:9 twist.

Good bullets, straight shooters (admittedly a little pricey).

[bm777]

the 80 grainers even, Lorgar..absolutely...yep they are a bit expensive...I have managed to get some Bergers $42/100 those were 105gr though..guys, not sure if you know, but here's the link:

http://www.q-store.com.au/collections/p ... get?page=2

Bosco

[Lorgar]

I have a brief go with the Bergers in a previous rifle ( .308 Win ) but couldn't get much out of them. Just not a good match.

My 7mm-08 is my regular now which I'm using 140gr BT in. I only do hunting these days so don't shoot heaps, a couple of rounds per trip so cost isn't an issue now.

The BT shoot under 0.4moa in my Tikka and with my small amount of shooting it's not worth changing. If I was shooting more I'd try and work up some cheaper loads, but not worth the effort as it is.

[troyboy]

I have a tikka t3 varmint 1:10 and the 2 hunting loads that I have worked up are 55gn nosler btip's and 95gn hornady SST's and it shoots both at sub MOA. I use the 55's for wild dogs but have shot a fair amount of big pigs with them to and the 95's for pigs.

I have never shot a deer so I cant really say what they would be like but they go good on 100+ kg pigs. As for target rounds I tried the SMK 95gn bullets but it sprayed them all over the place. Jump on youtube and look up 8541tactical. He seems to have some really good info and knowledge on all things about rifles. He states that its not so much the bullet weight that plays with twist rates but the bullets length has a lot to do with it.

Here is the vid where he talks about twist rates - https://www.youtube.com/watch?v=HVumE0yOxVw

[Lorgar]

SST's are another good one.

I've tried those in a few rifles including a .243 and they've always shot well.

95gr in my 1:9 .243 Ruger were great.

[Seconds]

I'm interested in a .243 Winchester as a varminting rifle, with the ability to handload some heavier stuff for pigs and the two smaller deer species (.243 is legal, correct?)

Yes, legal for the small species with heavy pills.

[Timb0]

Country bloke,
I use a Weatherby Mark V ultra light in .243 for hunting small deer and I love it! They don't make it anymore in that caliber so I don't know the twist rate but it stabilizes a 100gr Sierra GameKing which is a projectile I would recommend for Fallow and Chital Deer. I only go as light as 70gr Sierra BlitzKing and @ 3500fps MV they are flat shooting and very explosive out to 250yds
I also shoot a Rem 700 VLS in 243 it has a twist rate of 9 1/8. Once again I only go as light as 70gr but it dose stabilize 105gr Amax projectiles ( even though Amax 105 have a 1 in 9 recommendation) It loves 95 gr SST's that are also great for small deer.
I think you will have trouble getting good accuracy out of both ends of the 243 weight range with the one rifle. In fact if you have a twist rate that stabilizes 100gr projectiles, when you shoot 55 gr @ almost 4000fps it could cause them to spin that fast they start to disintegrate especially varmint rounds with their light jackets.
I would suggest if your going to shoot pigs and deer make sure your rifle is good for 90-100gr pills particularly Hornardy 95rg SST and Sierra GameKing 100gr. There is nothing wrong with 65-70 gr projectiles in 243 for varminting.
I use 2209 for the 100gr GK and SST's, 2208 for the 70gr BlitzKing and Vihtavuori N160 for the 105gr Amax. I'm anal I know!

[Apollo]

Spinning too fast is a falasy. It's got nothing to do with that, rather a manufacturing falt of jackets in the old days of, yes , being too thin for the lead slug inside.

These days the jacket can withold very fast spin rates and no longer a problem with great expansion without being like an FMJ.

[Warrigul]

Spinning too fast is a falasy. It's got nothing to do with that, rather a manufacturing falt of jackets in the old days of, yes , being too thin for the lead slug inside.

These days the jacket can withold very fast spin rates and no longer a problem with great expansion without being like an FMJ.

Nope, it still happens with some thin jacketed projectiles.

[Apollo]

Yeah, right....!!!!

Must be something to do with the thin air down south....

[Warrigul]

Yeah, right....!!!!

Must be something to do with the thin air down south....

Nope, we were stoking a new barrel on a 220 swift last year and it went faster and faster then on the next step nothing was hitting the target at 100m.

It can happen.

[subatom]

Spinning too fast is a falasy. It's got nothing to do with that, rather a manufacturing falt of jackets in the old days of, yes , being too thin for the lead slug inside.

These days the jacket can withold very fast spin rates and no longer a problem with great expansion without being like an FMJ.

The old problem was the bullet would come apart in flight right?

Big call to say modern jackets can't come apart at all? ever?

Askin...

[Apollo]

The simple story is that the "Lead" inside a bullet jacket expands when it spins and the jacket can't hold it....ie...it bursts in flight.

Pure physics.

Inferior jacket makers.....like those that want to turn .22LR spent cases into bullets... okay for a .22 Hornet but gee.... not accurate...cheap and nasty.

"Modern day jackets" can come apart... but.... if you are a major manufacturer... it doesn't want to happen or you are out of business.

[Timb0]

I know plenty of people who shoot 58gr - 95gr out of their .243 sporters on the once or twice a year hunting trip with no problem. These guys are not really looking to push the limits with speed, accuracy or distance. However some people who get hooked on varminting are. For someone who wanted to go that way I would say you should definitely try to match the twist rate to the projectiles you want to shoot.

I should have explained myself better then just leaving it at " the bullet could disintegrate " this is however the extreme end of what can happen if you don't get your twist rate correct at very high velocities. It's also a documented fact. I had a mate demonstrate it to me 6 or 7 years ago with what sounds similar to Warriguls story.

So speaking of simple physics, the problem actually starts from the large amount of heat generated by spinning a bullet that fast through the rifling. This can damage the jacket before its out of the muzzle and then it has to withstand the higher then normal RPM . In extreme cases this can be 100,000 rpm more than what its meant to be! The result is usually nothing. Nothing at all on the target or anywhere to be found!
The lesser end of not matching your twist rate are ; loss of velocity, loss of accuracy, increased spin drift ( long range), barrel life shortened ( not notice by most).

For anyone who is interested:
http://www.accurateshooter.com/technica ... stability/

[Warrigul]

I know plenty of people who shoot 58gr - 95gr out of their .243 sporters on the once or twice a year hunting trip with no problem. These guys are not really looking to push the limits with speed, accuracy or distance. However some people who get hooked on varminting are. For someone who wanted to go that way I would say you should definitely try to match the twist rate to the projectiles you want to shoot.
I should have explained myself better then just leaving it at " the bullet could disintegrate " this is however the extreme end of what can happen if you don't get your twist rate correct at very high velocities. It's also a documented fact. I had a mate demonstrate it to me 6 or 7 years ago with what sounds similar to Warriguls story.
So speaking of simple physics, the problem actually starts from the large amount of heat generated by spinning a bullet that fast through the rifling. This can damage the jacket before its out of the muzzle and then it has to withstand the higher then normal RPM . In extreme cases this can be 100,000 rpm more than what its meant to be! The result is usually nothing. Nothing at all on the target or anywhere to be found!
The lesser end of not matching your twist rate are ; loss of velocity, loss of accuracy, increased spin drift ( long range), barrel life shortened ( not notice by most).

For anyone who is interested:
http://www.accurateshooter.com/technica ... stability/

Our problem was we tried to repurpose a barrel that had a way too fast twist for the velocities were were previously getting out of a more common twist. The centrifugal force would have been way outside the norm.

We have a couple of members who really like to see the envelope pushed, usually there is no practical use for some of these trials and unusual gear but they are fun, stay safe and stick to loading tables.

[subatom]

"Modern day jackets" can come apart... but.... if you are a major manufacturer... it doesn't want to happen or you are out of business.

Fair enough. I thought it was still a bit of a factor, maybe that's just people really pushing the limits or something though and not average joe shooter.