.243 ballistics and bbl length??

stanman

I see that some of the popular "Tactical (jeez I'm sick of that word)rifles" in .308 are manufactured with a 20" tube.
I'm assuming that 20" then is adequate to nearly optimize ballistic performance for the .308 cartridge.
I would also assume, since the .243 is just a necked down .308, it too gets close to it's ballistic potential from a 20" barrel.
I have a Savage 99 in .243 with a 20 incher and would like to outfit it as my coyote and other large varmint/predator rifle.
I don't expect stellar accuracy from a lever gun with a rear locking action but I'm very fond of the Savage design and my other 99s exhibit good accuracy.
All I need is minute of coyote.
Does anyone have a source for the data on the .243 in 20" barrel??




"Extremism in the pursuit of liberty is no vice.
Moderation in the pursuit of justice is no virtue."
Barry Goldwater quoting from Cicero, I've been told.

D.S.COLE

I dont know of a 20inch barrel specific loading manual. The 243 bore is smaller than the 308 bore though they use the same case the 243 cant let the gasses burn and expand fully as quick ,because it is smaller inside. Ive read several times that a 20 inch 308 gets about all the velocity as a longer barrel most of the time. the 243 may not be quite as efficient. I do the rifle reloading for customers in our shop. The load of choice for a 243 with us is 39 grs of IMR 4064 and Sierra"s 85 gr BTHP Gameking bullet. This is the same bullet used in Federal Premium factory load that is also the #1 off the shelf choice here.
Most rifles shoot this with good accuracy and it is a deadly killing load on game. You may lose 50 to 100 fps in the 20 inch bbl. But that doesnt matter in the end result. The only way to ever really know the velocity is with a chronograph.
If this load doesnt group good for you, which would be possible but unlikely ,try IMR 4350 with the same bullet . Once in a while I run into one where this works better.