bsa airsporter mk5 0.22 under repair

[stonyat421]

hi all

i decided to strip down a bsa airsporter i have had sitting in a bag for the past 10 years
so purchased the usual bits that would need replacing /spring /seals /and so on
after stripping down the barrel because there was some old paint that needed removing ready for re blueing i noticed there was no drill whole for the front site so i assume the barrel has been cut down as i cant see any type of metal filler
so my question is what length should the actual barrel be and why would you cut down the barrel in the first place
is it possible to change the actual barrel only
and also can the end of the barrel actually be removed as this one has been so a new whole can be drilled for a front site
also would the barrel being shorter reduce the acracy in the gun

thanks tony

there is a gl stamp on the barrel