Grendel buffer tube?

[Jmccracken]

Looking to get a BA 18? rifle gas barrel. And as much as I love a rifle stock, probably going with adjustable on this build. What buffer/spring should I get?

I?ve been eyeing some of the lower build kits from PSA with the magpul ASC stock

[A5BLASTER]

Carbine buffer tube and carbine buffer and spring works fine for me.

[VASCAR2]

Same for me.

[Lowell Higley]

Usually, when I purchase an adjustable Stock for the AR platform, I get a Stock with the Spring and Buffer Tube as one purchase. So far, that has worked for me.
You are going to have to ask some one else about a build kit. I usually go on line to five or six different sellers of gun parts an shop. I have done it six times and it has worked out for me.