Looking for touch up pen to cover up a couple down to metal scratches on upper compliments of today's Colt QC philosophy.   Tried a blackening cmpnd from caldwells but it just works on steel.  this upper is alum I'm guessing.

What should I use??  Thanks


I've just received back from colt a 6720 bought new last august from ables.  Came in with purple upper.  They, Colt, replaced upper its nice and black but don't get why they even bother with crap like this. Took seven mnths to get it back.

Try alumablack

+1.

Worst case, testors matte black and a q-tip

Thanks.   ... I think Ill try an oil based satin or flat black with a trimmed modelers brush to just get in there.  Very small but definately visible nick.  If that doesnt work ill spend money on the alumablack.