Here is where I ordered my last one.

http://www.brownells.com/.aspx/pid=2...ML_BREECH_PLUG

As for being BH compatable. I use the Canadian version of the nipple and BH works just fine for me. I've even used the weaker/cooler ML primers w/BH and got it to go off consistently (though I do live in the south) I settled on STS primers and they work beautifuly.

Hope that helps
Scott