Sbr Questions

[gjohnsoniv]

I am new to the whole sbr/class III things and have a couple of questions. First, what forms do I need to fill out for a short barreled rifle? Second, what barrel length would you recommend. Finally, what muzzle break or flash suppressor would be the best to use?

[Seaslug]

If you're building the gun yourself (or having it built) on an existing receiver, then you'll use the BATFE Form 1. There are already existing threads on that process, so I won't go into detail here. As for your other questions, I'm afraid we're going to need a bit more information. I assume you're talking about an AR-type rifle, but I don't know that for sure. Can you clarify? Also, what will be the primary purpose of this particular rifle? Close quarters? General purpose? Do you ever intend to suppress it?

[gjohnsoniv]

Sorry I realized after I posted that question, that it was a little vague. Yes, I do want to build it on an ar platform. General purpose. At some point or another I would like to suppress it, but at the current time I am not as concerned about that.

[Capbyrd]

Flash suppressor would be determined by your choice in suppressor.

I really like the 10.5" barrels

[Seaslug]

For a general purpose SBR, I'd go with either a 12.5". Not as compact as a 10.5", but more reliable and significantly more muzzle velocity for shots at longer ranges.

I'm not a big fan of muzzle brakes on SBR's. Shoot one, and you'll see what I mean. It's like getting punched in the side of the head...lol. As for flash hiders, I'd go with a suppressor mount since you might suppress it down the road, anyway. My personal preference is the Surefire FH556-212a. Surefire suppressors are top-of-the-line, and even if you never get one, the 212a is still a pretty damn fine flash hider.

If you DO think you'll be suppressing in the not-too-distant future, I'd also highly recommend a complete Noveske upper with switchblock. The switchblock lets you regulate your gas system when switching between shooting suppressed and unsuppressed. The 12.5" switchblock upper is GORGEOUS...IMHO, of course.

[gjohnsoniv]

What about a 14.5" barrel? I know it would almost be a little pointless to have a barrel just a 1.5" shorter than a 16" barrel, but I am considering that. What barrels do you have on yours or like, also is it possible to buy just the switch block without the upper? As far as a suppressor goes, I have always wanted to machine my own rather than buy one. So in that regard it would probably stay on the short barrel more so than my other ar. Though I have heard very good things about Surefire and their suppressors/mounts.

[Capbyrd]

Clamp on switchblocks.

5.56mm Switchblock^®, Clamp-On - AR-15, M4, M16, AR-10 Variant Rifles, N4, N6, Leonidas, Recce Precision Battle Weapons - Noveske.com

Barrel and switchblock combos.

Barrels with Switchblock^® - AR-15, M4, M16, AR-10 Variant Rifles, N4, N6, Leonidas, Recce Precision Battle Weapons - Noveske.com

[gjohnsoniv]

Excellent, I will look into that. Though I might wait on that and put it on later when I get around to the suppressor.

[gjohnsoniv]

Oh, also am I correct in assuming that once I have the sbr lower, I can have multiple uppers for it? Such as a 16" and say a 14.5," or whatever?

[Capbyrd]

Thats correct

[PolePosition]

12.5" is probably ideal for gas cycling. Shorter than that becomes less reliable. And you want to use a flash hider instead of a muzzle brake. The brakes are designed for longer barrels, so not only will they be louder on shorter barrels, they will also overcompensate. Get you a Noveske 12.5" barrel (switchblock is optional. I don't think they are absolutely necessary) and a lightweight rail system like the KAC URX II or III. Flash hider like somebody above said depends on suppressor.

That's Noveske 12.5 with a different rail (edit...Daniel Defense) than I mentioned but gives you a general idea of what the 12.5's look like. That is with a Surefire flash hider as well.

Edited January 13, 2012 by PolePosition

[Dolomite_supafly]

Something else to consider is the type of suppressor. Some manufacturers will not warranty their suppressors on shorter barrels. I have used 10.5" barrels and consider those too short because you loose a lot of velocity. I wouldn't build a 5.56 gun with a barrel under 12.5". I consider 12.5" the minimum barrel for the 5.56 to be effective at anything beyond CQB distances.

A good thing about Noveske barrels is they act like barrels that are longer. A 12.5" barrel will have the velocity like a 14.5" barrel. A 10.5" barrel acts like a 12.5". If I had to have a 5.56 with a 10.5" barrel it would, without a doubt, be a Noveske.

Paladin Machine makes 2 or 3 position gas blocks for $75.

AR-15, AR-10 Adjustable Gas Blocks

If you have to have a barrel shorter than 12.5" I would forget about 5.56. There calibers that are better suited for short barrels than 5.56. There is a reason why the 300 BLK works so well with a 10.5" barrel. A 6.8 spc, 7.62x39 (if you can work out a reliable mag) or even a 458 SOCOM would be better suited than 5.56 in barrels shorter than 12.5".

Dolomite

[Seaslug]

Oh, also am I correct in assuming that once I have the sbr lower, I can have multiple uppers for it? Such as a 16" and say a 14.5," or whatever?

So long as you can easily re-convert the gun to its original OAL, as listed on the Form 1 (read: keep the original upper, or at least an upper with the same length barrel). As for your earlier question, I have a 7.5", a 10.3", a 14.5", and a 16", but each has its own receiver. Only the 7.5" and the 10.3" are SBR'd, as the 14.5" is pinned. The 10.3" wears a Surefire flash hider, and the 14.5" and the 16" wear Surefire brakes. They're all going to share the 556-212 I purchased last February if it ever makes it to my local Class III (darn BATFE).

I'm not sure I'd go through the trouble of SBR'ing a receiver if your only upper is a 14.5", but the multiple upper route is a good and cost-effective one.

12.5" is probably ideal for gas cycling. Shorter than that becomes less reliable. And you want to use a flash hider instead of a muzzle brake. The brakes are designed for longer barrels, so not only will they be louder on shorter barrels, they will also overcompensate. Get you a Noveske 12.5" barrel (switchblock is optional. I don't think they are absolutely necessary) and a lightweight rail system like the KAC URX II or III. Flash hider like somebody above said depends on suppressor.

That's Noveske 12.5 with a different rail (LaRue I think) than I mentioned but gives you a general idea of what the 12.5's look like. That is with a Surefire flash hider as well.

Good advice. Sounds familiar.

And the rail in the pic is actually a Daniel Defense RIS II Mk18. I've got the FDE version on my Mk18 clone (10.3").

[gjohnsoniv]

Well that answers my questions. I think I'll go with a 12.5" then. Also I think for me, at the current time I'm just going to go with fairly simple to start and get in the ring. Something that just came to mind, do you prefer your barrel to be exposed or the rail to come almost to the end of the flash suppressor? Or is that more of just a personal taste.

[Seaslug]

Well that answers my questions. I think I'll go with a 12.5" then. Also I think for me, at the current time I'm just going to go with fairly simple to start and get in the ring. Something that just came to mind, do you prefer your barrel to be exposed or the rail to come almost to the end of the flash suppressor? Or is that more of just a personal taste.

Longer rail = longer sight radius, more mounting real estate, and more surface to grip with support hand. The drawback to a longer rail is added weight.

[gjohnsoniv]

Great I think this answers all of my questions so far.

[Guest thorn]

Here's another option Rainier Arms, LLC™ | Browse | Muzzle Devices | AAC 5.56MM Brakeoutâ„¢ 51T Compensator

AAC actually recomends the compensators on shorter barrels to save the baffles, but as was already stated it is no fun without the suppressor.

[scoutfsu]

12.5" is probably ideal for gas cycling. Shorter than that becomes less reliable. And you want to use a flash hider instead of a muzzle brake. The brakes are designed for longer barrels, so not only will they be louder on shorter barrels, they will also overcompensate. Get you a Noveske 12.5" barrel (switchblock is optional. I don't think they are absolutely necessary) and a lightweight rail system like the KAC URX II or III. Flash hider like somebody above said depends on suppressor.

That's Noveske 12.5 with a different rail (LaRue I think) than I mentioned but gives you a general idea of what the 12.5's look like. That is with a Surefire flash hider as well.

That's Wes Grant's work. He does some amazing work and uses nothing but the best. Also, that's a DD rail

[gjohnsoniv]

Do you have to know your overall length before you fill out the paperwork, or after?

[Capbyrd]

Before. But thats generally easy to figure out. And if you are off by a tenth of an inch, its not going to be a reason for rejection.

[gjohnsoniv]

Great. That's what was a little bit worrying to me was if I am off by a little bit is that grounds for rejection, or having the ATF come after me for it.

[Capbyrd]

Nope. But tell us what you are planning and we can likely tell you exactly what your length will be. There aren't many combinations that haven't already been done. And even if they haven't, its not hard getting really close by using similar setups.

[gjohnsoniv]

12.5" barrel, thinking YHM Phantom flash suppressor, and I want to go with an A2 stock, but more than likely I'll go with a collapsible Magpul stock.

Edited January 13, 2012 by gjohnsoniv

[scoutfsu]

Stick with a collapsible stock. Why the YHM FH?

[gjohnsoniv]

Well I like the YHM Flash suppressor, but I am still open to better ideas.