AR SBR build

[FredBear86]

Wanting to build an AR SBR with a suppressor for deer hunting. What caliber should I go with? 223, 300 blk out, 6.5 grendel? Really wanna stay with an 8.5 inch barrel so total length stays under 16 inches. This kinda knocks out the grendel. This gun will be used on shots 50 and in. Possibly would do a 100 yard shot if the gun would do it, but mostly just want something to carry for close range shots in the woods. What's some recommendations?

 

[hereinaz]

IMO, .223/5.56 you want supersonic bullets, not .300 bo. The .22 ARC might be a bit faster, but I would not feel the need to go with a bigger case out to 100 yards max. You also have to start looking at barrel length for the suppressor you choose.

I am going to build a 10” upper in .223 Wylde (eventually) for that same thing.

 

[bombhunter]

For 50-100 and in, a 10.5 223/5.56 works great. Wouldn’t go shorter than that. I tested mine out for the first time this year and shot a couple of does. Both with 77 tmk’s. Performed excellently on both and was a dream to carry and maneuver in the tree stand. Even with a can on it. And a big bonus: practice ammo is cheap.

 

[justinspicher]

This sounds like an awesome project.

 

[WCT3]

I remember hearing about some 30 cal bullets designed to open up shooting subsonic. I have no experience with them but it sounds pretty cool and should work in a 300 blackout. Makes me think about building something to leave in my dad's safe for WI whitetail hunts...

 

[StupidLightweight]

At 8.5 inches, I’d go with 300 BLK, 338 ARC, or 350 Legend. For use inside 100 yards, you could likely go even shorter in barrel length. Good luck!

 

[Formidilosus]

Wanting to build an AR SBR with a suppressor for deer hunting. What caliber should I go with? 223, 300 blk out, 6.5 grendel? Really wanna stay with an 8.5 inch barrel so total length stays under 16 inches. This kinda knocks out the grendel. This gun will be used on shots 50 and in. Possibly would do a 100 yard shot if the gun would do it, but mostly just want something to carry for close range shots in the woods. What's some recommendations?

There are plenty of 223/5.56mm bullets and ammo that deliverfull upset and good terminal ballistics from ultra short barrels. The shortest I’ve used heavily is 5.75”, which gives nearly 300 yard upset range with some projectiles.

Having used all cartridges cited very heavily from short barrels, I am choosing 5.56mm everytime.

 

[Luke S]

I was wondering about this. I have a 7.5 inch 223 barrel laying around. I think I could keep a 77 TMK above 1800 fps out to 250 yards. Seems like a good way to build a compact backpacking gun. Any real issues with that as a close range bear gun? I'm assuming most of they guys killing stuff with 223s are getting a higher average impact velocity.

 

[stooxie]

Go 12.5" 6.8SPC-- shoots a 90gr bullet (i.e. Fed Fusion) at 2750fps all day long. That is excellent medicine for deer. An 8.5" barrel is going to struggle to spit anything out, no matter what caliber. I know you want short, but shooting at live animals, I'd encourage you to go a tick longer.

-Stooxie

 

[bombhunter]

There are plenty of 223/5.56mm bullets and ammo that deliverfull upset and good terminal ballistics from ultra short barrels. The shortest I’ve used heavily is 5.75”, which gives nearly 300 yard upset range with some projectiles.

Having used all cartridges cited very heavily from short barrels, I am choosing 5.56mm everytime.

Are there certain projectiles that you favor when going that short? I only have on game performance experience with tmks and the 73 eldm.

Edit: Experience with 10.5 and 14.5 respectively

 

[Formidilosus]

I was wondering about this. I have a 7.5 inch 223 barrel laying around. I think I could keep a 77 TMK above 1800 fps out to 250 yards. Seems like a good way to build a compact backpacking gun. Any real issues with that as a close range bear gun? I'm assuming most of they guys killing stuff with 223s are getting a higher average impact velocity.

It’s the exact combo and purpose.

 

[Formidilosus]

Are there certain projectiles that you favor when going that short? I only have on game performance experience with tmks and the 73 eldm.

All the same best performing projectiles at 20” are good at sub 10”. 69 and 77gr TMK, 73gr ELD-M, 62gr Fusion; 55, 62, and 75gr Speer Gold dots, etc etc. As long as impact velocity is about what is required foremost- the bullet has no idea what barrel length it was shot from. Even some heavier varmint bullets start work like a normal expanding version at sub 2,500fps impact.

 

[czgunner]

8" would be 300 BO. If you can go 12.5", that's ideal for 6.8 SPC.

Sent from my Pixel 3 using Tapatalk

 

[fwafwow]

OP - you may already know this, or it may not be relevant for your intended uses, but you technically need ATF approval for taking an SBR to another state. I’ve almost forgotten myself.

 

[IDVortex]

OP - you may already know this, or it may not be relevant for your intended uses, but you technically need ATF approval for taking an SBR to another state. I’ve almost forgotten myself.

I was actually looking into building a 6arc SBR for coyotes, but I'd be taking it to MT. Due to notifying them and what not, I decided to no longer do a sbr.

 

[98XJRC]

I ended up with an 8.5” 300 blackout. From the research I had done 14 years ago the supers outperformed the 5.56 in a similar barrel length. With that said I have no desire to hunt with subs and a 110/125gr does a fantastic job at the velocities you can get out of a 300 blk in an 8.5” barrel.

If wanting to avoid the paperwork portion build it as a pistol. One can only hope that someday SBR’s no longer require NFA stamps, but that’s where we are currently.

 

[BRTreedogs]

OP - you may already know this, or it may not be relevant for your intended uses, but you technically need ATF approval for taking an SBR to another state. I’ve almost forgotten myself.

I don’t think you need approval,
Your just supposed to send them a notification letter, my understanding is they very rarely if ever acknowledge it.

 

[Luked]

Looking at doing a 8.5" in 300 Blk for our "Alternative" deer season here.
My daughter shoots a 16" AR with the 125 Sierra Pro Hunters and its plenty accurate.
Havent got to see what they will do on game yet though.

 

[fwafwow]

I don’t think you need approval,
Your just supposed to send them a notification letter, my understanding is they very rarely if ever acknowledge it.

I think it’s Form 20 and it’s an application requiring an approval from the ATF.

 

[Chris_in_Idaho]

If you're starting from scratch on a form 1 sbr it might make more sense to start with an AR pistol so you can swap the stock for a brace anytime you don't want it to be an NFA item.

Any lawyers feel free to correct me, but my understanding is a pistol can be SBR'd and then revert back to pistol configuration at will, but a receiver that is initially a rifle can never be a pistol.