There are several 4350 alternatives that are closer than the 4831s:
IMR-4451 as
@INTJ suggests. Very close indeed to H4350 charges, pressures and MVs. (Data available online from the Hodgdon Reloading Center site.)
Norma 204, and a tad faster burning, URP.
Lovex SO65 (Shooters World 'Long Rifle' in the US) - a bit faster burning than H4350, around 1gn less charges in 7-08 with 160gn bullet, but an excellent powder in this application and the Creedmoor too. (Recommended by Shooters World for the cartridge and loads data on the SW website.)
Lovex SO70 (Shooters World '4350' in the US). On paper, it's a direct match to the 4350s albeit was regarded as the slowest of the trio when it was sold as Accurate Arms Co. 4350 at one time. (Different from the current Accurate-4350 from Western Powders.) However, the lot I have currently appears to be much slower burning and more like the 4831s.
Viht N555 and N160. Although burning rate charts usually show N160 on the same line as IMR-4831, it is faster burning and closer to the 4350s. In 7-08 with 160s, it uses around 1.0gn extra over H4350 for same MVs and is extremely well matched to this sort of application. (Do NOT trust QuickLOAD results for this powder though - they massively understate actual pressures!) N555 has been introduced by Viht to give the company a fully competitive 'player' in this popular niche. N555 charges are very close to N160's, but there is a full set of data on the Vihtavuori website's Reloading Data section for the Creedmoor
Alliant Re16 - gives very high MVs and reckoned to be one of the best powders around for temperature stability.
In ball powders: H414, Ramshot Big Game (bit faster burning), Ramshot Hunter (bit slower burning).