rounded hammer for ar-15

[SmileDocHill]

I need a rounded hammer to use with my CMMG .22lr conversion. I have a notched hammer in my large pin colt AR but I am almost certain that the "large Pin" is unrelated to this component, correct me if I'm wrong. I'll be at the 1500 Friday. I know there will be some there but if you are an individual or vendor it would be nice to know when and where you are and just meet and buy and save me a ton of time for toy shopping.
Any good online, individuals, or gun store referrals are appreciated.
I'm in Westfield, North northwest of Indy.

Edit: 6/14/10 I found ammo that works flawlessly without having to change out the hammer.

 

[SmileDocHill]

bump

 

[SmileDocHill]

I asked around at the indy 1500 today and this is an impossible thing to find. The "large pin" aspect of the early colt AR lowers does involve this piece and therefore it will be right next to hens teeth in someones supply drawers.