The Superformance 53g vmax is producing 3330fps. 22” barrel
Hornady 'Superformance' cartridges use specially blended and very high energy propellants to maximise MVs within allowed max SAAMI pressures. It is difficult, more likely impossible, to match their MVs with Viht single-based powders. N135 and N133 have nominal specific energy ratings of 3,550 and 3,600 Joules per gram weight which is relatively low compared to some. That's not to say don't try N133 as an alternative to 135 as it's better suited to this weight bullet in 223 Rem, and often groups tighter.
N100 Smokeless Powders | Reloading | Handloading | Single base Rifle powder - Vihtavuori
(Viht rates its N500 series 'high-energy' grades mostly at 4,000 J/g and other companies' equivalents are sometimes higher.)
Few rifles give their best at peak pressures and MVs. As
@Edinburgh Rifles says go by how well the rifle groups (and if you have a chronograph what level of MV extreme spreads you get from a shot-string with the bullet / powder combination). The final few fps you might achieve are also disproportionately hard-wearing on the barrel throat and leade.
However, if you really must chase velocity at any cost, consider Reload Swiss RS40, the canister version of that RUAG loads in the Swiss military GP90 version of the 5.56X45mm NATO. RS data ..........
Rheinmetall
......... show a max charge of 25.3gn RS40 for 3,458 fps from the 52gn ELD-M in a 600mm barrel at a hefty 3,913 bar (56,753 psi) PMax. The same powder under the 52gn Sierra HPBT MatchKing is listed at an even higher 3,481 fps from 25.5gn RS40 at yet higher pressures (4,030 bar / 58,450 psi). Norma case and RWS #4033 SR primer in both loads.
Two caveats. One, as with other Nitrochemie RS 'EI' powders, RS40 is known for hammering barrels if loaded to maximum levels. Two, at chamber pressures above ~54/55,000 psi, many factory rifles produce severely cratered and/or 'blanked' (pierced) primers with this cartridge due to a slack firing tip fit in the bolt face.
