It’s the full well defined bell-end, flared cheek pieces, looks late Corinthian to me - can’t tell if it’s got the ear holes or not. Apparently it was a bit of a problem that chaps wearing the old style bucket helmets couldn’t hear anything at all so instructions like ‘forward, march!’ ‘Fall back!’ And ‘suck my cock!’ Tended to be met with a universal ‘………. Sorry what?’ Which is not ideal, whether you’re inside a wooden horse or not