presicion barrell

Hey, So my friend recently aquired a tanaka m40a1 and wants to buy a tightbore for it. he knows about the 2roy conversion kit that would allow him to use vsr barrels and hops but he isnt comfortable with changing out all those parts. He is afraid he wil break something. He doesnt want me to do it for him cause hes afraid i might break something as well. So is there anywhere that sells presicion barrells for tanaka m40s? Ive looked around but cant really find anything for him.
any input will be greatly appreciated.