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-   -   .243 barrel twist?? (http://www.huntingnet.com/forum/guns/132435-243-barrel-twist.html)

game4lunch 02-10-2006 11:09 AM

.243 barrel twist??
 
I'm going to get myself a new rifle in a .243. I will be shooting a variety of store bought ammo from 55 grain to 100. What barrel twist would you recommend? I noticed for instance that the Savage is a 9.25" and Remington's is 9 1/8". Really that much difference out there 300 - 500 yards?
Brand name is of no importance, so long as it's Ruger, Remington, Savage, Browning, etc.
Oh yeah. I'm probably going to put a muzzle brake on it if that makes a difference.

ejpaul1 02-10-2006 11:28 AM

RE: .243 barrel twist??
 
Why the muzzlebrake?

longrifle1000 02-10-2006 11:33 AM

RE: .243 barrel twist??
 
I would imagine that one twist rate will not stabilize all bullets from 55gr to 100gr. Normal twist rate for a 243, will only stabilize 75-100gr reliably. Some guns do shoot the 55's ok, but most will not. But it really depends on how accurate you are expecting it to be with the 55's. If you are talking minute of coyote, I'm sure it will work. Good luck

game4lunch 02-10-2006 01:12 PM

RE: .243 barrel twist??
 
Primary use will be prarie dogs and cayotes.
But is a legal caliber in Wyoming. So, muzzlebrake because I could see myself shooting 200 - 300 times/day. I want reliability and accuracy out to 500+ yards.
And I suppose 75 grain would be alright. I'd rather lean towards the 100 grain "twist" rather than the smaller.
So, does the smaller bullets like more or less twist?
I read on another site that the .243 should be a 10" twist(?)
This is all kind of new to me, twist and all. I wouldn't have thought twice about it except a good friend said his T/C .243 didn't have "ENOUGH" twist to group tight at longer ranges.

hobie11 02-10-2006 05:54 PM

RE: .243 barrel twist??
 
the 9 1/8 inch twist will be fine but if i were you i wouldnt go lower than 75 gr. if you were gonna use the 55 gr for varmint using the 75 wont make much difference except more energy. if its pelt damage, all grains of bullets in .243 are the same diameter just some are longer and shorter.

zrexpilot 02-11-2006 08:39 AM

RE: .243 barrel twist??
 
I'm curious too. What kind of twist rate would be needed to shoot 55gr bullets.


Rebel Hog 02-11-2006 09:01 AM

RE: .243 barrel twist??
 
Quote:

ORIGINAL: zrexpilot

I'm curious too. What kind of twist rate would be needed to shoot 55gr bullets.


Encore and Contender barrels

Choosing Your Twist Rate
We have standards we recommend for various chamberings so you don't have to figure this out yourself. But if you'd like to know some guidelines and reasons, here they are: 17 Caliber: Use 1:9 for the rimfires and 1:10 for the centerfires. 22 CF (Centerfire): 1:7 is only for the heaviest bullets. 1:12 shoots 40-50gr bullets accurate in 223 and up to 55gr, accurate in 22-250. 1:14 is only for the lightest

[align=center]



bullets. 6mm/.243: Use 1:8 for 90-100gr bullets. 1:10 for 75-85gr. Use 1:12 for lightest bullets (ie. 58gr in 6PPC). On 30 calibers, a 1:10 twist is the best all-around. We DO build a few 30's in 1:8 twists for folks who shoot the heaviest bullets. The rule of thumb with twist rates is this: It is better to err on the side of too fast of a twist rather than too slow.[/align]

zrexpilot 02-11-2006 09:44 AM

RE: .243 barrel twist??
 
I'm trying to understand this. 1-14 is less twist than 1-10 ?
so lighter bullets need less twist ? basically ?

Rebel Hog 02-11-2006 09:54 AM

RE: .243 barrel twist??
 
Quote:

ORIGINAL: zrexpilot

I'm trying to understand this. 1-14 is less twist than 1-10 ?
so lighter bullets need less twist ? basically ?

Rifling twist rates
The rate of twist, expressed as one turn in so many inches (i.e. 1 in 10"), is designed to stabilize the range of bullets normally used in a particular caliber. It takes less twist to stabilize a given bullet at high velocity than at low velocity. At the same velocity in the same caliber, longer (pointed) bullets require faster twist rates than shorter (round nose) bullets of the same weight, and heavier bullets require faster twist rates than lighter bullets of the same shape. It is undesirable to spin a bullet a great deal faster than necessary, as this can degrade accuracy. A fast twist increases pressure, and also the strain on the bullet jacket.
Fortunately, the rate of twist chosen by the rifle maker is usually appropriate for the intended cartridge. Anyone ordering a new barrel for a rifle will generally do well to specify the standard twist as supplied by the major rifle manufacturers for that caliber.
Once in a great while, though, a manufacturer makes a mistake. One such case involved the .244 Remington. When first introduced, barrels for this caliber were made with a 1-in-12 twist, because Remington anticipated that their new cartridge would be used primarily for varmint shooting. The 1 in 12" twist is ideal for best accuracy with varmint weight bullets (70-85 grains) in a high velocity .24 (6mm) caliber rifle. The heaviest spitzer bullet that a .244 with a 1 in 12" twist barrel could stabilize was 90 grains. The customers, however, also wanted to use their new .24 caliber rifles for hunting medium size big game, with 100 grain bullets. Needless to say, customers ignored the new .244 Rem. Remington soon saw the error of their ways, and changed the rifling of their .244 barrels to 1 turn in 9", but the damage was done. Sales remained so slow that eventually Remington had to discontinue the .244. The following year they reintroduced the exact same cartridge as the 6mm Rem., and produced all 6mm rifle barrels with 1 in 9" twist barrels, which can stabilize all .24/6mm bullets. This solved their marketing problem, and 6mm rifles began to sell.
The usual twist rates for some of the more popular rifle calibers are given below. (For a more comprehensive list, see "Common Rifle Barrel Twist Rates" on the Rifle Information Page.)
[ul].22 Short = 1 in 24"
.22 Long Rifle = 1 in 16"
.223 Remington = 1 in 12"
.22-250 Remington = 1 in 14"
.243 Winchester = 1 in 10"
6mm Remington = 1 in 9"
.25-06 Remington = 1 in 10"
.257 Wby. Mag. = 1 in 10"
6.5x55 Swedish Mauser = 1 in 7.5"
.260 Remington = 1 in 9"
.270 Winchester = 1 in 10"
.270 WSM = 1 in 10"
7mm-08 Remington = 1 in 9.25"
7mm Rem. SAUM = 1 in 9.25"
7mm Rem. Mag. = 1 in 9.25"
.30 Carbine = 1 in 16"
.30-30 Winchester = 1 in 12"
.308 Winchester = 1 in 12"
.30-06 Springfield = 1 in 10"
.300 WSM = 1 in 10"
.300 Win. Mag. = 1 in 10"
.300 Wby. Mag. = 1 in 10"
.303 British = 1 in 10"
.32 Win. Spec. = 1 in 16"
.338-57 O'Connor = 1 in 10"
.338 Win. Mag. = 1 in 10"
.35 Remington = 1 in 16"
.350 Rem. Mag. = 1 in 16"
.375 H&H Mag. = 1 in 12"
.416 Rem. Mag. = 1 in 14"
.444 Marlin = 1 in 38"
.45-70 Govt. (Marlin and Ruger rifles) = 1 in 20"
.450 Marlin = 1 in 20"
.458 Win. Mag. = 1 in 14" [/ul]
Not all rifle barrels of the same caliber have the same twist rate. A fellow ordering a custom rifle may have his own ideas about twist, as may the builder. For example, some .270 Win. barrels are rifled with a 1 in 12" twist, some .30-06 barrels are also rifled 1 turn in 12", and some .300 Magnum barrels are rifled 1 turn in 14". Usually these variations make no great difference. These slower twists may give slightly lower pressure, as well as very slightly better accuracy with the lighter bullets in each caliber. They will still stabilize the heavy bullets over practical hunting ranges. However, they might not be such a good choice, or quite as accurate, for shooting heavy bullets at extreme range (like 600-1000 yards).

Roskoe 02-11-2006 12:12 PM

RE: .243 barrel twist??
 
This twist thing is kind of interesting . . . . it applies more to the length of the bullet than the weight. You can make up for lack of twist by adding velocity, but ittakes a lot to make even a small difference. The main hard and fast rule is that if you don't have enough, you are screwed. And if you have too much, you may still be OK.

For instance, in my 1:10 twist 6MM-284, I can stablilize any 100 grain bullet; but not the 105 A-Max or the 107 Sierra VLD. I tried the 55 gr. Ballistic Tips a few years ago and to my amazement they shot about 3/8" at 100 yards. The "ideal" twist for this bullet is probably around 1:16, but the groups didn't suggest there was any sort of problem. In theory, I should have been able to get a little more speed before I ran into pressure problems, with this light of a bullet, with a slower twist. But I was happy with 4387 fps. Only problem was that it blew a 4" entry hole into a broadside coyote.

There are also some atmospheric factors. Bullets a sea level in cold damp climates are harder to stabilize than bullets in thin air at high altitude here in the west. This was an issue with the original M-16's issued back in the late 60's and early 70's. They had a 1:14" twist and, shooting a 55 gr. FMJ bullet, were working well until the troops up the artic started complaining they were having trouble qualifying . . . .


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