I am looking to build a 20" varmint/long range upper with free float hand guard. My question is, should I go with the 20" with the standard thread end for a comp or just a non thread end.
these are the barrels I am looking at [b]here[/b]
Also should I go with the 1/9 or 1/7. I don’t reload and am looking for a twist that can handle what every ammo I can find.
Thanks for the input.
I say thread it. You’ll be able to use a suppressor or FH and as ridiculous as this may sound its possible that it will be illegal to thread a muzzle after Change happens and if you decide to make it a combination varmint rifle/tactical rifle, it needs threads.
Sorry, don’t know what twist is best
Yes have it threaded.
Why?:
Options.
There are a lot of muzzle devices that will fit this thread pitch, from Flash Hiders, to Muzzle Breaks, to Supressors.
Ease.
Down the road do you really want to have to disassemble your upper just to ship out the barrel to have it done? Why, when you can have it done before you install it.
Re-sale value.
Goodluck selling it without threads, thats one more thing I need to send it out for before I put it on MY rifle.
Thanks guys, look’s like it is the thread barrel 
thread it
if you change your mind later you can but a thread protector and your barrel will look as before again 
ETA: as for the twist ratio…1/7 will handle bullets from 50gr to 77gr while 1/9 “only” up to 69gr: get the 1/7 if you can but the 1/9 will serve an average shooter (like me) great!