question about twist rate?

Question

so if I buy a rifle barrel(.223) with a 1:8 twist, it will shoot all the normal ammo, I wont need a certain grain ammo or anything right? It just means that the barrel will be more accurate, as long as im shooting straight and accurate.

Answer 1

1:8 will do fine for the usual weight range. It may overstabilize some really light bullets, but that isn't likely to come up.

Answer 2

.223 Remington and the military 5.56x45 are not the same as far as how the pressure is measured .Also the the throat of the barrel maybe have a different " relief" amount. Some ammo can be fired in both military and civilian arms depending on bullet weight and rate of twist.

It think it would be best to use .223 Remington in civilian guns so marked. AR15's and civilian version, you might have to be concerned about bullet weight or risk red-lining the pressure bar..

Answer 3

Different twist rates perform best with specific bullet weights. This is another way of saying that for each bullet weight, there is a best twist rate for that bullet. You can calculate the best bullet weight for a specific twist rate or the best twist rate for a specific bullet by using the Greenhill formula. It is a bit of a lengthy explanation for this venue but if you will go to the local library and find a copy of "UNDERSTANDING FIREARM BALLISTICS" by Robert A. Rinker it is in there. Look in Chapter 12 on page 141 for an explanation and an example of the equation. Your rifle should shoot all of the common bullet weights with reasonable accuracy but if you want maximum accuracy, you will need to use the Greenhill formula to calculate te BEST bullet weight for your rifle. Since the .223 round is an inherently accurate round and is frequently used for varmint hunting, you probably should do the calculations if you want to use your rifle for varmints or accurate target shooting.