i tried those home blueing kits and they are not that good . you have to repeat the process several times to get a o.k. job and if you have any heavy spots of rust you will never get a pro finish. the chemical from what i understand is poisonous so you have to be careful and wear gloves. i learned this the hard way with a lot of wasted time and energy. if you want a nice deep black finish you have to get your barrel hot blued. the last gun i had done it cost me around 100$ but it looks brand new. just my experience but unless there are other options i never heard of a good one.