Hornady load data not adding up

Hey guys so Im just about to start load development for my 308 win. Im running a proof research 20" carbon barrel. Running Lake city brass, 178eldm bullets, and Win 748 powder. I loaded up some rounds to break in the barrel and chose a powder charge a little higher than the middle of the published load data (43.3gr). Published max is 45.7 grains. Published FPS for 43ish grains is 2400fps Im assuming with a 24" test barrel. The max 45.7 grains published FPS is 2500fps. I was thinking I would be getting somewhere around 2280-2300fps with the short barrel. I hooked up my magnetospeed and ran 5 rounds over chrono. 2557,2558,2557,2557, 2549. I thought that was crazy high speeds for a 308 running a 178 bullet over a 20" barrel! Also had a little sticky bolt lift indicating pressure that I did not expect to run into couple grains below max published charge. No other signs of pressure. Has anyone ever experienced pressure signs significantly below published max? This is actually the first time ive ever experienced pressure signs under published max. Either way it still shot great ES SD and 1/2" grouping at 100. Exploded a soda can at 1k yards the load too. Too bad Ive got to change the powder charge.