Re: 9mm AR with Timney trigger...anyone??
I edited my post above to clarify any confusion, but I'll expand here a little more.
Whether you need a ramped BCG all depends on what you are doing with the rifle. The problem is that there is a notch on the top of a standard AR15 hammer that will catch on the 9MM bolt and prevent it from returning to battery. This will lock to bolt back part way and prevent you from opening the top of the AR15 to fix the lock up and you'll end up removing the buffer tube, spring and buffer to release the pressure on the bolt, then driving out the hammer pin to get the stuck hammer to move out of the way enough to get the damn bolt out and to clean up the whole jam (which takes a good bit of time and is a royal PITA)!
If your 9mm bolt is ramped, you can use any hammer you want whether it be M16, AR-15, 9mm dedicated, etc.
Ramping the bolt removes the ledge that gets stuck on the standard hammer notch. Some DPMS hammers will work without modification to the hammer or the BCG, as will other triggers.
The Timmney triggers are set up with a rounded/radiused hammer so they will work with 9mm as well, including non-ramped BCGs. I recommend the CMMG because it will allow you universally to use any AR-15 trigger unit on the market without concern for function/reliability.
Sorry for any confusion in my earlier post. Needed a few more cups of coffee this morning before I hit the keyboard!
