WAG = wildassguess
Sure, Remington did make the Model 6 single-shot available in .32 - but AFAIK only with a 20" round/tapered bbl.
The Remington Model 25 was yet another made in .32 cal (.32-20) - and IIRC the early versions had octagonal bbl, as in the OP.
But those are facts, not a guess - which is what I took, in the absence of anything more significant from the OP in the way of identifying characteristics for his rifle.
whaddyasay, kmsqrd2 ?