243 Winchester
Here you go http://www.shootingtimes.com/ballistics/243_winchester.html
The twist rate in a Winchester 670, 243 caliber is 1:10.
Introduced in 1955 for the Winchester Mdl 70. Proper name of the cartridge is the .243 Winchester.
The 243 Winchester caliber was introduced in the model 70 bolt action and the model 88 lever action rifles in the year 1955 by Winchester.
The popular 243 Winchester originated as a wildcat based on the 308 Winchester brass necked down to 243 caliber, Warren Page developed the first prototype of this cartridge, it was then made available as a factory cartridge to the public by Winchester in 1955.The 243 Winchester is the first true dual purpose class of cartridges, loaded with lighter bullets it is an extremely effective varmint round, sending a 70 grain bullet out the barrel at 3,500 fps., this is enough for any varmint sized game at the 400 yard mark, however load it with 100 grain bullets at 3,000 fps. and you have an excellent deer and antelope round good for 300 yards.My own favorite bullet weight is 87 grains which serves the dual purpose of varmint and deer cartridge.The 243 Winchester is a light recoiling round which is comfortable enough for anyone to shoot, and it is inherently accurate which is a bonus to all that own a rifle chambered in this round.For a beginner just getting into the high power rifle sports the 243 Winchester round is highly recommended. Also for anyone that is recoil sensitive this is a great rifle cartridge.243 Winchester Barrel Specifications.Common Barrel Twist Rate - 1 in 10" & 1 in 9" (uncommon) 1 in 12".Bore Groove Diameter - .243"243 Winchester Reloading Specifications.Bullet Diameter - .243"Maximum Case Length - 2.045"Trimmed Case Length - 2.035"Primer Size - Large Rifle243 Winchester Loading Data Hints.The 243 Winchester most common barrel twist rate is 1 in 10" but if you have one with a twist rate of 1 in 9" or 1 in 9 1/2" then you'll find that the 243 will give its best bullet performance using 100 grain bullets with slower burning powders like I.M.R.4831 powder.243 Winchester Reloading Data.Hodgdon Reloading Data Center.243 Winchester Reloading Dies.RCBS Full Length Die Set, 243 Winchester.243 Winchester Shell Holder.RCBS #3 Shell Holder For 243 Winchester.243 Winchester Bullets..243 (diameter) Bullets, by Sierra, Barnes, Hornady, Nosler.243 Winchester Unprimed Brass.Winchester and Remington Bulk Unprimed Rifle Shellcases, 243 Winchester.243 Winchester Ammunition.Hornady, Remington, Winchester, 243 Winchester ammunition.243 Winchester Rifles.New Browning, Remington, Winchester .243 Winchester rifles here.243 Winchester Trajectory and Hunting Applications.This is a down range trajectory chart for the 243 Winchester cartridge with the scope mounted 1.5 inches above the bore center line plus if you were using this load, its effective hunting bullet energy range with well placed shots on,Varmint / Predator size game, such as Bobcat, Cougar, Coyote.Deer size game, such as Antelope, Blacktail, Hogs, Javelina, Mule, Whitetail.Elk size game, such as Caribou, Black Bear, Sheep.Moose size game, such as Brown Bear.Bullet diameter .243"Bullet weight 100 grainsBullet ballistic coeffecient .376Bullet velocity 3,100 feet per secondRange100 yds.200 yds.300 yds.400 yds.500 yds.++ 1.50- 6.8- 19.9- 40.71788148612281009825Varmint++++++Deer+++---Elk------Moose------
Winchester introduced the .243 Winchester cartridge in 1955 for the bolt-action Model 70, and the lever action Model 88. As far as the year of manufacture of a particular rifle, you will need to provide the manufacturer, model number and serial number to trace it, but if chambered for .243, it logically cannot be early than 1955.
Made in 1957.
No such model number
a serial number is needed to give you an exact age of your rifle.I can say that your winchester in .243 cal.was made between 1956-1973.
Normally a rifle chambered for .243 Winchester would be built on a short action.
Are you sure that you were sold right ammo? I know it sounds obvious but we had a guy bring a 7mm-08 Tikka in saying that the ammo didn't fit and he'd already bought the rifle in and we'd sent it to the manufacter to be checked. I had a look at the box and say he'd been sold 7x57mm aka 7mm Mauser. You may have been sold .243 WSM (Winchester Short Magnum) or .243 WSSM (Winchester Super Short Magnum) instead of .243 Winchester