5.56 vs 223

[dannywayoflife]

I was just wondering what is the difference in chambering between a 5.56 & 223? I know the throat is longer on a 5.56 but is there any other differences? I ask as I've been looking at some reloading data and it states much higher fps with 5.56 with the same bullets.

 

Thanks

 

Danny

[bradders]

The throat is longer as you state, but they are also generally just a bit bigger in diameter in the neck as well

[dannywayoflife]

Interesting thanks mark.

[gbal]

Is it not very unusual for the 223 not to chamber in the 5.56,and somewhat unusual the other way round,but possible.If so, case differences are slight,with the 5.56 a tad bigger,esp neck,as said,though internal volume/capacity will also depend on the case construction-maybe heavier in 5.56? Commercial 223 brass does so vary. .

However,bullet velocity is very seldom given with pressures,and it may well be that ' military' loadings are to higher chamber pressures,and thus velocities,even with the same grade of powder,and above SAAMI sporting maxima.

As may well be some high mv's in varminting loads in any cartridge case.Pressures are just never measured,but as a first approximation,if velocity is above SAAMI,then so is pressure likely to be.'No symptoms' of pressure is a tad naive-even if true.Medically,some symptoms are not symptoms of the incipient disease,but of it's now teminal stage of development..last warning,not early hint!

Fortunately,there are usually some earlier signs for shooters,usually....

Gbal

[bradders]

The ammunition whether .223 or 5.56 has the same dimensions (you never see a set of 5.56 dies after all).

It's the chamber dimensions in the barrel that differ

[gbal]

The ammunition whether .223 or 5.56 has the same dimensions (you never see a set of 5.56 dies after all).

It's the chamber dimensions in the barrel that differ

Agreed-strictly speaking SAAMI specs are chamber specs.

5.56 chambers may be more tolerant(looser or longer?) to accomodate wider production batches of ammo,perhaps?

Nothing to get too Wylde about!

The velocity diffs if any have more to do with the internal volume differences of the brass,and the loading pressures.

Maybe too different military loading for different uses-like LMG use?Just a guess,never seen any measured pressures etc.

 

Gbal