Not by Much...
If it is that close, and your accuracy is good now, i would just work on the air-seal.
I would get into the hop up first, (bucking, nub) to start with, and maybe a o-ring nozzle for the gearbox (I bought an aluminum one for $9 shipped on ebay) all to increase the efficiency of your air seal.
My primary is a 4 year old classic army m4 pro-line that i had to replace the cylinder head when it finally snapped after 30,000+ rounds.
While i had it down, I bought an aluminum cylinder head(shs), aluminum o-ring nozzle(shs also), a new piston o-ring, a guarder bucking & nub.
Total rebuild investment? less than $45, and shoots better than it did new.
Factory Length barrel, (the suppressor is just the look i want)
45 Bravo