Core & Main tumbles on FY sales forecast cut

** Shares of water pipe distributor Core & Main CNM.N down 18.33% at $54.35 premarket

** Co narrows FY sales forecast range to $7.60 bln to $7.70 bln, from previous guidance of $7.60 bln to $7.80 bln

** CNM says lowered guidance reflects higher operating expenses and softer residential demand

** Co posts Q2 adj. EPS of $0.87, missing analysts' estimates of $0.79 per share, according to data compiled by LSEG

** Reports Q2 revenue of $2.09 bln, missing analysts' estimates of $2.14 bln, according to data compiled by LSEG

** YTD, stock up nearly ~30%