Just to let everyone know, Jard Adjustable triggers ($135) Brownells, Midway, etc. will work with Colt Style Uppers and the bolt does not need to be ramped.
The trigger kit consists of a 4-way adjustable trigger, (Overtravel, Sear Engagement, Disconnector, and Safety), and light weight hammer. They come is several weights and are very reliable.
It took me about 1.5 hours to install and adjust. With the trigger spring that came with the kit I got a 1.5 lb trigger pull, clean, crisp, and a tactile reset. I put in a different hammer spring, and the pull increased to 2.25lbs which is much more to my liking. The take-up is near negligible, and the pull feels like a nice 1911 trigger.
The only catch is to be liberal with the loc-tite that comes with the kit. If not used, the adjustment screws will walk out, and the whole thing will need to be adjusted again.
I put this together with my RRA 16" 9mm upper, VM-Hytech Lower with VM-Hytech mag block. Now I just need to reload more 9mm.
I don't work for JARD, but I like there product, and with all the questions about bolt ramping, and what hammers to use, I thought I would put this out there.