First off let me say hello. New to the forum. I can see theres plenty to read which is great. My buddy put me on to the site being I have some questions regarding an SBR build.  I built an AR last year and have had a blast doggin it out. Been interested in building my first SBR in 300 blk so here are some of my questions if anyone can help Id greatly appreciate some feedback.

- Buying the lower reciever... After that whats my next step? Filling out the paper work for the tax stamp for SBR?

- Whats the ideal barrel length for the build? I'm considering either 10.5 or 11.5 with 4 inch can but im going what ive heard dont have i guess the adequate insight for making the decision.

-Anything particular i need to know about buffer springs? Im leaning towards running sub sonic ammo from what ive read seems cool but then again like i mentioned im a newbie to that.

- Barrel... Probably very dumb question but im guessing theres 300 blk barrels? Lol sorry

I guess those are some of main questions I have in my head right now.
Looking forward to checking out any feedback.

Going to be checking out plenty of related threads in the meantime.

Welcome to the forum!

I'll be putting in the paperwork for a 300 BLK SBR when I get the extra cash.

I built a pistol in the meantime so I can possess and use the upper.

I went with an 8.25" upper from Hardened Arms. The gun runs great with few hiccups, and the few failures it had I believe were due to not shouldering it. Hopefully when I SBR it it will run 100% with a stock installed.

If it still chokes I'll have to look into buffer and spring weights.

I'm sure others will chime in and post their opinions/experiences.

There is a lot of knowledge here.

Good luck.

Welcome to ARF

Yes, purchase a lower (or build your own from an 80%'er), and then decide how you wish to manufacture the sbr, either individual or trust.  I recommend a trust.  Then, fill out your paperwork, get your $200 extortion fee cashiers check, and send all that off the ATF (which should be a convenience store and not a .gov agency)

They'll likely cash your check the day they receive it, or within a week or two tops.  Now you wait for their gracious and benevolent approval for you to be able to exercise your natural right.  

The popular barrel lengths for 300 sbr's are almost universally in the 8"-10" range.  If you plan to shoot subsonic a lot, I highly suggest going with an 8" barrel. If you want a slight increase in MV and/or longer handguards (carbine vs midlength), I'd consider stepping up to a 10" barrel.  That said, many users have 8" sbr's and use them in both subsonic and supersonic with great success.

Standard carbine buffer spring with a H or H2 buffer is what many use.  I was using a Spikes ST-T2 buffer before I got the LWRC UCIW stock kit.

There are many makers of 300 barrels, and many happy users of many of these makes.  Everything from Ballistic Advantage (my personal fav  for cost and features) all the way up to Noveske, which are known to be accurate barrels. but they do command a premium.

Additionally, if you plan to file a form 1 to sbr, I would also start looking into suppressors and get that going as well.  You can form 1 of those as well or purchase a quality, proven can from a number of retailers. NFA hoops and $200 extortion fee cashiers check apply as well.

Here's a little inspiration...

Awesome info thanks again. Love the extortion fee line LOL!!

Dont want to bother too much with questions and just read up on the feedback but about the trust... How do I go about obtaining that?

Check out this forum.

A lot of good NFA info there.

http://www.ar15.com/forums/f_6/22_Class_3_Firearms.html

why 300 blackout?

To have a .30 caliber projectile that uses standard everything of a 5.56mm AR-15 except the barrel.

Lower, magazines, BCG, etc.

Because from what I've seen, read and heard until now it seems very versatile.

I was more asking the original poster why he wanted 300 Blk.

The cost of 2 tax stamps and a suppressor is what tuns me off, among other things. But lots of folks seem to like to like it so who am I to say.  


There any validity to what this guy has to say?  http://www.alloutdoor.com/2014/05/22/300-aac-blackout/

First off, the Whisper was originally formed from the Fireball cartridge and not 5.56/223 IIRC

"Will not function without a suppressor or some funky pistol gas system" is competely wrong.  My sbr cycles super and sub, suppressed or not.  That is a function of the port size, poet pressure and dwell time.

And he goes on again about how "it was meant to cycle subs" with a suppressor and supers without.  False again.

The author then goes on to compare the 300 to some 5.56 rounds, etc, but fails to make any mention of barrel length.

He then goes on to talk up the 25/45 which, while neat, and another option, is limited on projectiles that may be loaded to mag length while still achieving good velocity.  (If you want a 25 cal 224 variant, I suggest getting into the 25/223)  And again, no mentiin of barrel lengths used to achieve those numbers.

Goes on to talk about 308, 458 Socom, and a bit more blah, blah'ing.  

He addresses some of the cost, but completely overlooks the fact that 300 can be handloaded, in both super and sub, for SIGNIFICANTLY less.  That said, premium factory 300 ammo costs no more than premium ammo in most any other caliber, so that's kind of a moot point.

He then says his preference for a 300 build would include a 16"+ barrel.  I have no idea why he would want a 300 with a barrel longer than 16", but hey, it's his money.

His statement about reliability with any supers other than the "hot" 110gr loads is patently false.  Again, mine chews through it all.  110gr, 147/150gr, 220gr, etc.  Many others have no issues with reliability and cycling.

Finishes off his story talking about razors and how a single razor somehow cuts better than modern tech.  Again, more opinion, not much substance.

All in all, only some of the things he stated were true, the rest was just opinionated rhetoric and was only reflective of his experience.  Countless others on this board would tell him different.

Yes, I do like the 300.  No, it's not a 308, and if you want 308 power, I suggest getting a 308.  But the 300 is very unique.  It's a "jack of all trades" so to speak.  It's not the single best in any one category or metric, I know this, but it does have versatility and utility not found in any other double-stack AR15 variant (223 or otherwise).

And it's also president proof.  223 brass and 308 bullets are probably the two most plentiful reloading components you'll find in north america.

Food for thought

You make some great points, thanks.

Sorry for the derail

If you get a trust you can file the Form 1 online and pay with a credit card.

Thanks but how do I obtain a trust? Whatsbthe process? Do I have to go somewhere to obtain that. Thats one point im lost in.

A number of places online offer trust services, and the price is rather reasonable (~$100-$200).  You may even find a local attorney that will set one up for a reasonable fee.  Laws vary state to state so it is often recommended to have someone knowledgeable with your states laws draft it for you.

That said, it is not a requirement that you have an attorney draft it.  I created my revocable living trust with Quicken Willmaker.  I am somewhat familiar with my states laws and I modified my trust accordingly, adding legalese and provisions for NFA specific items.

The ATF has never blinked at it when I have sent it in.

Here is an article that gives a good description and provides some good advice.  I did my trust with an attorney that specializes in firearms.  Cost more but I have someone I can work with if the needs arise.  NFA Trusts

Do do I complete the form 1 first and submit to the ATF along with the fee or must I do the trust first?

You need to establish the trust first because you need to put the trust information into form 1

ETA: You need to submit a PDF copy of the Trust paperwork with your form 1

Noted. Thanks

Highly recommended that you build it as a pistol first to make sure everything is gtg. If all is well, strip it back down and have the lower engraved with the necessary markings, THEN send in your form1.



It sucks finding out the lower is out of spec or the engraver screwed up and your form1 is already in process. You can cancel the stamp provided the SBR has not been built yet but it takes a while for a refund.

yes.

Make sure you lay in a pile of primers.  The one thing that you cannot make/reuse.