cutting a 20 inch down to an 18

[dale]

hi,
any thoughts on negative gas system affects by shortening my 20 in upper down to 18"?

what could i expect to pay a competent gunsmith to cut & rethread the barrel?

thanks ahead

[Edward78]

The Gas systems are the same on a 16" and a 20" bushmaster barrels so shortening it down to 18" should give you no problems. As for gun smithing work it varies allot but it should not cost a arm and a leg I have thought about doing the same thing with my 20" barrel 18" is the perfect barrel length for the 450B for me.

Ed