I am thinking about getting a Colt that has the large size fire control parts. Other than the fact that you need to get these special size parts if you ever need to replace a broken piece, are there any other drawbacks?

I see that Bushmaster sells large part complete sets for $50 so I will get a set to squirrel away for the future (Do I need to or should those parts always be readily available?).

Other than having to get your parts from Colt only,and paying that higher price,no. I think the parts will be around for awhile,so I don't think you need to stock up.

There are companies selling the replacement parts for Colt rifles now, but I don't think that it is worth the hassle in my opinion. Buy a Bushmaster and then you don't have to worry about it.