Re: Euroarms 1851 Navy, Shooting High
You may have to put a higher front sight on it, or see less front sight when shooting. The longer the bullet is in the barrel, the more time the gun has to recoil and shoot higher. Heavier powder charges produce more recoil. The combination of total recoil and time recoiling determines how high it will shoot. This is easiest and usually determined by trial and error vs mathematical calculations.
I am not familiar with the Euroarms brand. Most Italian repo revolvers in nominal 44 cal.will only hold about 33 grains of FFFg Black Powder (by weight) and have room to seat the ball. That is typically the way I load and shoot them sealed with Crisco shortening or lard. The 19th cent. originals (excepting Walkers) held more powder, and were not known for breaking fully loaded. I do not understand why your brand would have a 28 grain max recommended charge, unless it is made from inferior materials (possibly Spanish). It should be made from at least 60K psi low carbon steel. I doubt you could get enough Black Powder in it to generate 12K psi. behind a round ball. Still, better safe than sorry. I am not advising exceeding maker limits, even though they seem low.
I also keep a cleaning rod with a bronze bristle brush in my range kit. I brush the barrel well after every cylinder full to preserve accuracy from residue build up.