Lightest/shortest 300 Blackout AR?

[Tyler Kemp]

Wanting to build a suppressed SBR 300 Blackout with my buddy.

How short of a barrel can I go and still reach 1000 fps with 208/220/240s? Will there be a large difference in noise going short?

Mostly going to be used for hunting, so I thought I could use the smallest contour barrel possible, and a whatever stock is handy and light?

 

[velillen]

If I remember right the blackout is designed to fully burn in 8" of barrel. Most sbr 300 s I have seen barrel wise are 8, 8.2, 9, or 10 inches in length. Haven't really seen shorter than 8.

As for the 1000 fps Mark...even in a 8 inch barrel you'll have to play with your powder charges to hit where you want. The book minimums are usually in the low 900s or even upper 800s from my experience so it's just a matter of starting at the minimum and working up to where you want it

 

[brcook03]

Unless specifically stating otherwise, any of the factory sub loads will be loaded to ~1000 fps in a 16" barrel (SAAMI spec) and will be slower in the 8-10" barrels. If you're handloading, you can adjust charge weights in order to meet your goal.

 

[gpz750]

There are 7" barrels available

 

[jwb47]

you never start low and work up with subs you start high and work down . less chance of sticking a bullet in the barrel if you look at all powder manufactures sub loads they all give a load for around 1100 fps . just an fyi yankee hill says they will honor a warranty for a can on a 300 black barrel down to 8 inches . I would think the others would also . none of the bullets you stated are very good for hunting . check out lehigh defense maximum expansion and outlaw state 220 grain fracturing bullets they will expand down to 700fps .
I have an 8.5 inch barrel for the record

 

[JD0x0]

Have you thought about a MSAR bullpup? It'll give you more barrel length in a shorter weapon than most standard carbines.
MSAR

OAL is 27.2'' with an 18.5'' barrel

An M4 carbine with a 14.5'' bbl and retracted stock is still longer at 29.75''

 

[Travis S]

Have they actually put one out to the masses yet( msar 300blk)?

 

[Tyler Kemp]

The thing is I don't need barrel length since I'm going subsonic. That MSAR looks cool, but pricy and less practical.

 

[rjacobs]

If you are handloading you will tailor your load to your barrel anyway. The 9" AAC barrels are GREAT. The 8.5" Noveske barrels are also excellent. Definitely want 7 twist for the heavies IMO. Most of the lower priced barrels are 8 twist, which isnt bad, but I prefer 7 twist. If you go with a cheaper barrel, be prepared to play with the gas port to get it to run right. Thats the #1 issue I see with any of the cheaper barrels. You never see guys saying "my AAC" or "my Noveske" doesnt run, but you do read about most of the cheaper barrels having issues.

And if you are strictly using it for hunting the 208 amax, 220g and 240g SMK are terrible choices as they will simply pass through whatever you hit. The 194g expander from Lehigh is AWESOME, but pricey at close to $2 per loaded round. BUT 100 of them SHOULD get you through at least 1 or 2 hunting seasons depending on how much you hunt. Use the 208's or 220's as your practice sub loads which you can load for around 60c including brass cost.

Look around on 300blktalk for a TON of info and loads and what not.

I see you are in Missouri. Im over in St. Louis. Let me know if you want to meet up and play with my 300blk setup some time.