BB,
I've done the triggers on both my 7mm-08, and the .223. I had a problem with the 7mm-08. When I put the trigger group back in, thinking all went well, the hammer wouldn't lock up. When I took it apart again, I found that the hook on the hammer, had snapped off! I was able to reshape it with a dremel tool, but also ordered a new one from Numrich Arms. The new hammer was listed as being for a SB-1, and it not only fit well, it also has a different hammer angle that allows the scope to be mounted lower. I can't say that I know if the sporsters internals are the same, but the SB-1 parts work well. BTW- The trigger on my .223 needs a strong thought to fire. It came out even better than I could hope for. I did make sure it wouldn't fire if it got jostled a little, by banging hard on the rifle with my hand. I have a book somewhere on dismantling rifles, I'll dig it up and see if the two rifles, SB-1 and Sportster, are listed together for dismantling.
Don