223-222m powder capacity

[bheadboy]

interesting experiment

I took a fired 223 lc case and a fired 222m rem case then very carefully weighted each case.

following that I filled very slowly/tap vibrate down- each case with lt 32 a fine powder - to the mouth flush (as if I was using water)

then weighted them again, to my surprise the 222m has 10% higher capacity by weight of the powder.

other powders do virtually the same.

when I compare this result to the loads I developed by ladder using powder that are not listed in the 222m data bases I found the sweet spot to be between +8-10% and the velocity of all those tested hitting this sweet spot to be within 25fps of each other and all shooting in the .300's for 5 shots

the difference in powder performance I find to be ES and some sign of pressure - Lt 32 was the powder that started this test as there is little load data for it.

Bob

 

[mikegaiz]

The 222 Rem Mag has more case capacity (it is longer) than the 223. it was designed that way. ???

 

[bheadboy]

well aware the 222m was around before the 223, tried for the "m16"round did not feed - redesigned with shorter case, less angle of the shoulder and higher cup case spec to arrive at the present 223 round,

my point taken was the use of powder as a substitute for water and arrived at similar results % difference

shot loads arrived upon by this method very well.
my first br hv rifle was purchased from Robert Hart a 40x 222m. in 1966

Bob