I re-blued the barrel on my rifle. Turned out great. I re-blued the magazine, but the blue wouldn't take in some areas, and in other areas it turned black. Any advice?

What kind of blueing did you have done and what kind of rifle is it?

Some metals will blue differently than other metals depending on the make up of the steel. Take a hardened steel Springfield receiver. It has more nickle in it and will blue a completely different shade of "blue" than a modern chrome molly barrel. There is nothing that you can do about it.

Basically the more carbon that the steel has in it the darker the steel will blue. Steel is a controled rusting and the blueing salts attack the carbon as the carbon is what actually rusts.

Also if there is anything that has been hi-temp soldered like a bolt handle or sights the solder will not blue at all. It will stay silver.

Same thing happened to me when I refinished a sporterized M96 Swede, the barrel buled really nice but the receiver didn't. I'd say BB has the right answer seeing as what his education is.

Assuming you're talking about a cold blue, you might try a different brand. I've found some metals take Brownells's Dicropan best, some 44-40, etc. Not all cold blues work equally well on all metals.

well, I polished the magazine with steel wool, sprayed it with WD40, let it sit over night, then cleaned it with blue remover and tried again. This time it turned out perfect.

BTW I'm using Perma-Blue cold blue liquid.