.223 / .224 cal projectile size confusion

[on_one_wheel]

Right o, I'm a bit confused.

Why am I reading on the internets that the projectiles that I need to reload my .223 come in boxes marked .224

Cheers

[Baldrick314]

.224 is the true projectile diameter of centrefire 22 rounds. Sounds confusing at first but it's just one of those things like .303's really measure .312

[happyhunter]

.

[<<Genesis93>>]

This is a can o worms topic....

But yes most 22 centrefires use .224 (technically 0.2244 as they are 5.70mm - metric spec) diameter projectiles while most 22 rimfire chamberings use 5.72mm / 0.2252"

What confuses is the naming;
some chamberings use an arbitrary number that does not represent either the bullet, bore or groove diameter such as the 222 or 223REM which are derived from the board room opinion.... (bullet 224, bore 219 groove 224)

Others use the bore dimension: 6.5 Rem Mag
or the groove diameter: 264 Win Mag

^Those 2 chamberings use same diameter bore (6.5/0.2559) different projectiles (technically) 6.72/6.73, swaged down on firing to a 6.71mm barrel, thats another complication -

some chamberings use a proj undersized to the groove (rifling engraved on firing only) eg 303Brit, 6.5x55SE

others use a proj sized to the groove, so bullet fits the barrel with rifling engraved eg 7.62x39(AKA 7.62 Soviet) and 375H&H Mag

.
.
.
Whenever a 223Rem is discussed the 308win is not far off; so the 308Win uses 7.85mm/0.3091" bullets and the barrel measures 7.62/7.82 (0.300/0.3079)

see, easy

[on_one_wheel]

Thanks for clearing that up fellas.

I won't be missing out on a bargain next time I see .224 projectiles for sale on buy swap and sell.

[Herdsman]

It's a dogs breakfast the way all our cartridges and titled