.223/5.56 reloading question

[cricco]

Greetings fellow reloaders. I have a simple question, that I'm sure will draw debate. LOL! Today I was reloading some ammo for my MP15. I started loading Winchester .223 cases. At some point, I began loading NATO marked Winchester 5.56 cases with the same load. I am using 25.9 grains of Ramshot Tac behind a 53 grain Sierra HP Matchking bullet. Which should be pushing about 3100 fps with the .223 cases. My Sierra book lists something like 26.7 grains as a max load. I'm guessiing that these will be ok to fire, but I thought I should double check with some of the experts here first. Will the NATO cases cause any signifigant changes that could be a problem?

 

[gerrycaruso]

I think military brass is thicker than commercial brass. If thats true then the military brass will not have the same capacity. See how much water each case will hold,then you'll know.

 

[cricco]

I think military brass is thicker than commercial brass. If thats true then the military brass will not have the same capacity. See how much water each case will hold,then you'll know.

I measured the NATO cases against the standard .223 cases, and all the measurements are identical. The weight of the .223 case was 95 grains. The NATO case was 95.4 grains, which could be attributed to residue inside the case. If the capacity is different, how will that effect the C.U.P of the charge, if at all?

 

[m4bushy]

you should be ok. The standerd rule of thumb is to back off your loads 10% with military brass. That is about .3 grains with the load you are using. You are .8 grains from the max load you listed.

 

[EddieCoyle]

If the capacity is different, how will that effect the C.U.P of the charge, if at all?

If everything else is equal, the case with the smaller volume will develop a higher pressure.

pV = nRT

It's the law.

 

[cricco]

Thanks guys.

 

[WILDCATT]

223

the general rule is military cases are thicker but the 223 /5.56 are the same.

 

[squeeze]

Those military cases are baby killers. PM me and I'll dispose of them for you, at no charge even.

As stated before, sounds like you're not pushing the max load so have fun.