i have some brass with RED coloring on the base,does any one know why ??? Thanks

In a ring around the primer? Factory primer sealant.
The entire head, on range pickups? someone was using red marker to identify them.
Other than that I don't have a clue.

Cartridge brass is of course an alloy of 70% Cu and 30%Zn. To get red out of that it was probably some type of corrosion that brought out the color of the copper.

If the whole head of the case is red You may have some cases from factory proof loads. Do not reload those cases.

primer sealer.

Snowman may be correct, although all the Proof Loads I have seen have had a purple color on the case head, I have not seen any proof loads in several years.
I was given a couple of hundred fired cases in 44 Mag that were proof loads. I still use them. they have worked fine.
Also some people mark their reloads that way. When I got several different loads from Superior they had different colors on the base of the shells so I could tell the different loads apart.[The 286gr. and the 320gr. Woodleighs look the same once they are loaded].

[ 07-27-2003, 22:25: Message edited by: N E 450 No2 ]

Will the "color" polish off??

Thanks for the info--I too think its a proof load,just wanted to check

Kynadog is correct! It is a primer sealer that some companies put on their brass. I have reloaded and shot these casings with no problems.