Driving a roll pin through the trigger guard without the trigger guard between the ears is really risky, that's how the broken ears happen. If you support the bottom and put the trigger guard in, you can hit it very very hard without any risk at all of broken ears.i drive the roll pin threw the trigger guard before i install it , makes easier the 2nd time, dont like how hard i have to hit it first time driving it in on the receiver, saw one on here with broken ear,
Alternatively, you can get this: http://www.rainierarms.com/?page=shop/detail&product_id=1237
Which is a magpul aluminum trigger guard that has been modified by rainier to use two screws instead of a roll pin. You pay an extra $10, which may not be worth it to some. I got mine in last night actually and installed it in about 30 seconds. I'd buy it again in a heartbeat, and I've installed more than a few trigger guard roll pins without issue.