I have a rifle I  built in 2002 on a RRA lower w/Mod1 kit. Since then sold off the HBAR upper,etc and put a Colt A1 upper on it. With both uppers had a problem with the bolt carrier catching before it went into battery. I determined that the hammer was catching on the fp collar so chucked it in a drill and filed it down. Trouble is now the collar is too small and falls inside the hole in the bolt carrier. My question is will the rifle be safe to fire as it is, or do I need to get a new fp and hammer?I am starting to think the hammer might be the issue since it is much thicker than the hammer on my colt rifle. BTW had to reduce collar that small to allow it not to snag on hammer.

Get a new firing pin and try a shrouded carrier.

ETA:
A safety concern with your firing pin would be that because it can slip further into the carrier, it can potentially protrude out the bolt face in the unlocked position. This would create a danger of an out of battery firing. If the firing pin got stuck forward in the carrier by hooking what's left of the collar, it would likely not go into battery and could very likely fire the round attempting to be chambered. The floating firing pin doesn't have enough mass to fire the round when the carrier is travelling forward, but if the carrier was pushing the protruding firing pin when it stopped against the base of the cartridge, that would be where you could have a slam-fire.

Get a new firing pin, and as suggested the shrouded carrier will eliminate your problem.  But there is something else wrong if your hammer is catching on your firing pin.

Shrouded bolt carrier or un-notched hammer should solve the problem.

With an unprotected carrier and a notched hammer I've had the firing pin collar hit the hammer hard enough to mangle the FP retaining pin. But never caught enough to stop the action of the rifle, just destroy a FP retaining pin every 30-rounds.