The 550 action can be slicked up with very little effort. I use JB Bore Bright on the bolt. This is a mildly abrasive paste. Slather up your bolt with the JB, and spend a bit of time working the bolt fore, and aft. About 500 cycles did wonders for mine!
One caution though, do not turn the bolt handle down while doing these cycles. The abrasive paste could work it's way onto the back of your bolt lugs, and therefore alter the headspace. It would be very minor if this happened, but it is something to be avoided! And, of course, flush the action clean afterwards with a good crud cutter type of cleaner. I think you will be very pleased with the results.