Missing Decimal Places After Cast()-ing

Hello, The issue is to convert a number like 114270 to 114 + (270/320) = 114.84375. The decimal version is the desired result. In other words the last 3 digits of 114270 are in base 320.

Question: I cast my number as char() then use substring() to get the digits. Then I cast back to float and divide by 320. I get 0 when I do this and I'm not sure why.

Code follows:
declare @p float
set @p = (select top 1 P from [tablename] where Product = 'Z')

declare @pchar as char(6)
set @pchar = cast(@price as char(6))
declare @first3 as char(3)
declare @second3 as char(3)
set @first3 = cast(substring(@pchar, 1,3) as float(25))
set @second3 = cast(substring(@pchar, 4,6) as float(25))
select @pchar -- 114270
select @first3 -- 114
select @second3/320 -- 0

I have tried changing cast(substring(@pchar, 4,6) as float(25)) to
cast(substring(@pchar, 4,6) as decimal)
and I get the same result. Any suggestions or is there a better way altogether?