T.P.13,

Just remember this, if you switch to aluminum blade grips (HM or MicroHeli), you ARE more likely to break many more parts upon a crash. The plastic blade grips are CHEAP INSURANCE against breaking more expensive items, such as the feathering spindle, center-hub, or the mainshaft itself.
You can repair broken plastic blade grips by CA gluing the ball end back on, then drill a 1/16" hole thru the center of the ball end into the blade grip itself, insert a piece of 1/16" diameter piano-wire into the hole and secure it with more CA glue, cut the wire flush. This method works great when the LHS run out of replacement blade grips.
I've also seen guys buy 3.8mm ball ends and screw & glue them to the plastic blade grips, so you end up with a plastic blade grip with a metal ball end, still 10 times safer than going to aluminum blade grips.

Rick