5.56 Ammo Question

[RabbleInArms]

Can some share with me the difference between FMJ and MCBT 5.56 ammo?

Thanks.

 

[drm-hp]

Normally, an fmj is a flat base bullet with the back end of the jacket open exposing the core.
A mcbt is normally fully encased in a jacket w/ a boat tail rear profile.