I have used several kits but the one I think are the absolute best is the patchworm.
http://www.patchworm.com

I noticed a 14mm barrel with a very diffrent finish on my US comp to other 510s ive seen. Does anyone know if its a diffrent type being used on the US?

Changed to a standard shroud on my US, like it better this way and also enjoying the UNF option. What do you think?

I do not know for sure but When I was looking for the samething I thought there might be a hamster that you mount pn the euro rail and that goes backwards. Line the ones on some Steyrs.