Last fall I bought a couple of pick up loads of ammo from an estate.  Most all the ammo was still in the original boxes inside of ammo cans.  I have been looking through the ammo cans (ammo cans were filled with whatever fit not like kinds) and organizeing the ammo by like kinds.  Last night I came across a can that was full of  ammo that appeared to be Win. 5.56 but it was packaged in glad bags.  Each bag had 100 rounds in it, each bag was marked .223 / 100rds.  The case is headstamped WCC 77, I pulled the bullet and it is 55gr. and powder measurement is 28.5.  The powder is ball but it appears to have 2 different powders in it,  the primary powder is small but there is about 1/4 of it that is about twice as big a round and kind of flat edged ( looks like you had a roll and sliced it up).  There is primer sealant around the primer.   I am just trying to figure out if this is a factory load or a reload.

Was there asphalt or black stuff around the bullet? If there was, it's a factory load, and would be M193.

Yes, the bullet has a black tar looking ring arount it.   If this is a factory load, why the 2 types of powder? or is the larger stuff some type of flame retardant?

Pics of the powder?  If the fine stuff is really fine it is probably a burn inhibitor to slow the burn.

Factory ammo is not made with canister grade powder.  They use whatever works best for the round's required velocity and pressure.  To do this, they constantly check their powder's qualities and tweak the load as they go.  One arsenal batch of powder may need a slightly larger powder charge to meet requirements, while another may need a smaller one.  There are also requirements about throat erosion, flame temperature, gas pressure at an idealized gas port, and a number of others.  The plants make the ammo work within specs by doing what's needed, that's all.