So I've done a little research on the steel case vs brass issue in the past. What I found out is that steel case ammo does not expand as much as brass . That means at times the steel cases do not expand and seal the chamber completely . When this happens gases and crap can blow back and get into the chamber , carbon can then start to build up . If your only shooting steel ammo you should be fine cus with the lacquer and other finishes they use the cases should still be slick as snott and cycle fine . As long as you start with a clean chamber with no build up already.
I also here if your shooting alot of steel ammo in the same day you do not want to switch to brass ( the first few mags have steel the next brass ). The reason I here is the carbon and posible lacquar build up in the hot chamber can cause the brass cartridge to adhere to chamber wall and fail to extract and that can destroy an extractor or rip the rim off the case
So only shoot one or the other per trip or per cleaning and always clean your chamber really well after shooting steel cased ammo . I clean mine with lots of bore cleaner , a chamber brush and a T-handle . I push that brush in and out a bunch of times then I push it back in and spin it 20 or 30 times .Then finish it off with a dry mop and patchs . If you do not clean the chamber really well after shooting steel ammo or really all ammo the carbon can continue to build up and create problems with all ammo being shot thru the gun .
It makes sence to me . Im not sure if there is any science behind it but thats the way im going to do it .
check this link out . It gives a good desciption of this issue
http://www.theboxotruth.com/docs/edu18.htm
As far as what steel ammo works the best . I would think its like most other ammo to gun matchs . Some guns like some ammos more then others .Your just going to have to try some out and what works for you is what you use