I’m new to this, so be patient with me. Can anyone tell me about the contents of this box?
Do those have a rebated rim? I seem to recall that they do because of the lightweight bolt assembly they are used with.
Would this cartridge case be properly called a 5.56x45RB instead of 5.56x45mm?
As it defacto is made for a 5.56x45 chamber it should be named like that.
As otherwise all other cases longer or shorter for technical reasons would be renamed too and cause a mess.
I can see the discussion which will start now…
Yes, the rim is rebated.
Obviously a safety factor…a 5,56 gun with a Trainer Light bolt will not lock on a normal 5,56 Cartridge head…so no chance of firing Ball 5,56 in a Trainer bolt fitted rifle!!
On the other hand , a Trainer cartridge in a Ball ( heavy bolt) rifle will fire safely, but may not extract
( low gas pressure).