Who makes a decent 13.7” 300 blk barrel?

Odd size for a 300 BLK.

Whats the plan with it? I don't know of anybody that makes a factory 13.7...

Want to shoot subsonics. Just want to consider my options if the ATF goes through with this stupid point system.

Are you planning on getting a can?

If not, not sure 300 BLK is really worth the squeeze in that case.  Your money, but that's my take.

And if you ARE getting a can, then you're obviously okay with NFA, in which case I'd just F1 SBR it, and go buy an ~8".

I’m waiting on a sandman S and I also reload so pretty excited to load subsonics. And you’re right…we’ll worth the $200.

If you'll be going that route, I'd urge you to consider something in the 8 inch ish length. Especially reloading. You can custom tailor subs and supers you can gain back most of the lost velocity from going shorter.

Ballistically..
Go 8-9 or 16. Nothing else really makes sense.
Factory ammo specs are 16". Only way to reasonably close the gap between barrel lengths is load your own or stick with 16".
If your plan is a can then 8-9 is what you seek.
Depends on your goal..? Hunting, Quiet as possible supers, suppressed, I would go 16’.
General all around, not sure..?..but compact as reasonable...8-9 with a can fits nicely.

I have a Noveske 8.1. I only shoot supers now, hunting. 110vmax works just fine under 125 yards.

Topic Moved

It might be difficult to remain subsonic in that long of a barrel.  The bullet will keep accelerating if you give it more steel to run in.  The reason for the 9"ish barrel is to easily keep the bullet subsonic.  There are cans that have a shroud that can be P/W to the barrel to make it a one stamp gun, and keep the barrel around 10" give or take.

I have two 300 uppers that I built.  One 10.5" and one 16".  Supers run fine in both of them of course but so do subs.  I experimented with a fair amount of ammo trying to find what my uppers like (seems they are not picky so that's good) and all marketed as subs have stayed subsonic in the 16".  Generally 220 to 230 grain.

I have little practical use for subs, but I do shoot them occasionally as it is so quiet and fun. Just expensive and ballistically not ideal for most applications.

I have a 7.5", no regerts.

Shoots subs and supers fine, but my main goal was suppressed subs.  It's a 1:7 twist, which is more than adequate for any big heavy bullet you can stuff into it for a sub load.

Supers it tends to favor 150's over lighter stuff, possibly due to the twist.

I'd have no issues taking deer out to about 200 yards with 150's.  I expect in a suppressed sub CQB situation, it'll do fine with the 225 grainers.

I also put a binary trigger on it, which makes shooting the subs a lot of fun.

When/if the ATF's new stupid "rules" go into effect August 1, then I've decided I'm dropping another $200 and form 1 it as an SBR.  No more worries, no more hassles, and lots better options for accessories without worrying if I'm in compliance with some set of BS laws (let's face it, it IS laws, effectively) whimsically created by unelected officials.  Not worried about the restrictions for taking it across state lines, etc.  Don't have a lot of reason to do so, besides have plenty of other options if I feel I need to bring a long gun with me.