Since I couldnt seem to find much info here are the main differences I noticed so far:
Spikes Nickel Boron Bolt Carrier Group:
$225
All Mil Spec
HPT/MPI
Viton O-ring
Mil Spec Extractor Spring
Longer(mil-spec) extractor pin
Rguns
$150
Non-Milspec(or would that be run of the mil?)
No HPT or MPI
No O-ring on extractor
Extractor spring plain bronze spring(quite weak too..chucked that pos)
Almost too short Extractor pin(not sure if this is the correct term...holds extractor in place)
Both do use the black extractor insert. The Rguns does have a happy face on it which is kinda funny/different
I have ran close to 400rds through the Spikes BCG and its definitely gtg...havent tried the Rguns yet...bout to head to ORSA and do that. I didnt have an extra viton o-ring for the Rguns, but I did replace its extractor spring with a Wolff extra power one...so we will see what she does. If it runs as good as the Spikes its probably a worthwhile alternative for the non-hardcore when you figure in the $75.00 savings.