What to know before build an SBR - Feed me your knowledge

[GregSmith]

I've been kicking around the idea of building an SBR for fun and for something lighter that my wife can comfortably use. What's the basic process in building one. Doesn't have to be detailed, but I don't know some things. Assuming we made a trust for the SBR so we both could share responsibility etc.

1. Can I buy all the parts and then do the paperwork before it gets put together?

2. Do I have to buy the lower and designate it SBR before purchasing any other parts?

3. If I just build an AR pistol and wanted to throw on a stock to transition into an SBR, is that legal?

4. 7", 10.5" is that personal preference and what consideration are there to make in deciding.

5. Any other tips or tricks or words of experience you want to throw my way before I do this?

Anyway...a quick 411 on the basic ins and outs of an SBR would be great. I didn't see any threads about it on the forum.

Thanks in advance!

G

[Nathanb]

You are not supposed to have the parts available to turn it into an sbr before you have the stamp. So not having the barrel in your possession is what many say to do.

You can buy parts before the stamp comes back. They are just parts

Yes you can.

Caliber dependent. The shorter you go the more velocity drop you get and the louder they get. 300blk is a different story from 223

Try to keep your gas system as common as possible the shorter you get and have to run pistol gas or things like that the more people have issues. I have an 8.5 300 blk and a 10.5 223 and both have carbine length gas. That's probably the most common thing people have issues with. Other than the shorter barrel it's really just an ar

[RangerTrace]

I didn't build either one of mine, so I will leave that portion of the answer to the guys who have done it.

Assuming you're going with 223/556, I think the length of the barrel depends on a couple of things. Will you ever put a suppressor on it and do you plan to carry it in a small covert bag? If you don't plan to carry it in a bag, I see no real reason to go shorter than 10". I have a 10" LWRC and I had no issues hitting steel out to 350 with mine last week using an Aimpoint PRO. If the real purpose of the rifle is for your wife, you might consider a 9mm SBR build using a mag block. The 9mm is cheaper to shoot and if you decide to suppress it, they are super quiet. And if you decide you want a 225/556 or 300 B/O, all you gotta do is buy/build the upper and remove the mag block.

[dauntedfuture]

You can have all the parts before you put things together, however you could get into trouble as you have the ability to put an NFA item together without the stamp. With that said, suppose you have one SBR lower and two SBR uppers and you buy another complete lower, by the same token you could get into trouble, in reality i dont there is an issue with the second set of circumstances however the possibility exists.

You can buy a pistol and then add the stock after you have the stamp back and thats the route i would go so you can actually shoot the thing and get it working first. You would need to buy the pistol or get a stripped lower and build the%2

[dauntedfuture]

You can have all the parts before you put things together, however you could get into trouble as you have the ability to put an NFA item together without the stamp. With that said, suppose you have one SBR lower and two SBR uppers and you buy another complete lower, by the same token you could get into trouble, in reality i dont there is an issue with the second set of circumstances however the possibility exists.

You can buy a pistol and then add the stock after you have the stamp back and thats the route i would go so you can actually shoot the thing and get it working first. You would need to buy the pistol or get a stripped lower and build the pistol, you cant build%

[OPENB]

A lot of people build it as a pistol while waiting on the stamp. I settled on 11.5", as I saw a lot of problems with lengths shorter than that with gas. The same rules of dwell time apply with SBRs. I friend had a 7" Adams Arms piston gun, but the velocity loss was huge. 55s were barely 2150fps., and it was obnoxiously loud. Having all the parts before having the stamp is constructive possession, and people have been prosecuted for it. Lots of good info for SBRs over at ar15.com.

[NoKimberDave]

I built a 7.5" pistol gas with sig brace. I then filed my paperwork. When approved I sold the sig brace and installed the stock I wanted.

I have since added a 12.5" carbine gas barrel, because I wanted a 12" handguard. It's about perfect for a lightweight gun for factory division. So much fun.

Obnoxiously loud with a brake. But it works fabulously. As does the 7.5", it works so well I can't understand why people have problems with them. I think it is key to buy good parts that fit together well.

I used aero precision barrels with their gas blocks and they run like a top!

[63expert]

Buy a stripped lower. It is transferred as "other" so you are allowed to posses a barrel less than 16". When you get your stamp you can affix a rifle stock.

Once you have an SBR lower you can have as many short uppers as you like. You don't want to get into a situation where you have more rifle lowers than 16" uppers to go on them.

For your first SBR you may want to stick with a 10.3-11.5 carbine upper as those are known quantities to start with.

This is my 10.5. Aero Precision barrel and BCG. DPMS A2 upper, Magpul MOE SL stock and handguard, MIAD grip. This rifle has run 100% with LC M855 and my 2500fps 55gr reloads.

Edited December 18, 2015 by 63expert

[dogtired]

If you have an Ar you want to use, send in a Form 1 and $200 and wait 6 months. Buy parts or a built upper and once you get the stamp, snap them together.

The AR is a great host for the SBR as the lower is considered the firearm, the upper is just parts.

Edited December 19, 2015 by dogtired

[jmnielsen]

Since you didn't say what caliber I'm going to assume 5.56.

You didn't mention it, but if you are planning on running suppressed you may plan barrel length around what suppressor you would like to buy. I know some are rated down to 7.5" but most are not.

Also consider its intended uses. Close range plinking/fun gun? Or something that you can take to 200-300 without issue if need be?

For your reference I'll tell you what I did and why. I built a 12.5" middy with .223 wylde chamber because I wanted a "do it all" rifle that wasn't terribly long with my suppressor attached. It is an accurate rifle that I use for 3 gun, coyote hunting, plinking, and training. I have a 1-6 scope on it so it's good close and i can still run it out to 300+ no problem. Since it's a 12.5" barrel, I can shoot VMax out to 200 or so and still be above their minimum expansion velocity for shooting coyotes. I actually sold my other 5.56 after it was built because this filled every role I needed it to.

[Mike41]

If you get your stamp is it only good for the one SBR and can the stamp be use for a silencer or is a 2nd stamp needed?

Mike

[RangerTrace]

If you get your stamp is it only good for the one SBR and can the stamp be use for a silencer or is a 2nd stamp needed?

Mike

One stamp for the SBR and one for the Suppressor.

[MJN1957]

Assume a trust....

You were smart going with a trust.

1. As previously stated, don't have all the parts necessary for a SBR until the stamp is approved. With an AR, the one thing that is SBR specific is the barrel (not surprisingly). To be safest, pick your preferred barrel length, get everything but the barrel in-hand, then order the barrel - or upper - after the stamp is approved. Will you go to prison if you have the barrel/upper before the stamp? Unlikely, but not impossible.

2. In effect, you will be registering a serial number that will be required to be on your SBR build. You don't HAVE to own the lower, but it certainly is a best practice. How else will you 'lock-in' the serial number if you don't own it before you file the paperwork?

3. Building a pistol first is a common work-around and it is completely legal. You can even use a carbine receiver extension (just don't put a stock on it until the stamp is approved, not even to "pew-pew-pew around in your bedroom).

4. There are practical considerations to barrel length and safety considerations. A proven SBR recipe for 5.56/.223 is 10.3"/10.5" and this has the added advantage of working for most suppressor restrictions while a 12.5" 5.56/.223 is a good 'middle ground' that isn't as finicky as a 10.3"/10.5" can be. For a .300 BlackOut, it is designed around 9" with 10.5" common since it works well with typical carbine length fore-ends. Go carbine-gas on a 5.56/.223 (you can stretch it to mid-gas on some 12.5" barrels) and definitely go pistol-gas with a .300 BlackOut.

The safety consideration is to think really long and hard before you go any shorter than you are used to on the fore-end. If you go with a super-short barrel/fore-end - less than 9" - be extremely cautious when switching between rifles/uppers. If you are used to a standard carbine-length fore-end, then switch to the super-short SBR upper and reach toward the front of the carbine-length fore-end you are used-to, you can either grab air with your hand in front of the muzzle, or grab a potentially very hot suppressor. Either can result in extremely unfortunate circumstances. I've witnessed the former and I've inadvertently done the latter. I was wearing gloves and still got a warmer reception that I liked. The guy who I saw do the latter lost all 4-fingers and a substantial part of his left-hand. YMMV.

5. NFA firearm ownership can be idiosyncratic. They are NOT treated like 'standard' firearms in several important ways. If you'd like me to expand on that, let me know.

MikeN

Edited December 27, 2015 by MJN1957

[GregSmith]

5. NFA firearm ownership can be idiosyncratic. They are NOT treated like 'standard' firearms in several important ways.

Yes, please expand if you have time. knowledge is power.

Also, what happens when people pass away with NFA stamps/rifles? Can they be passed onto family members? if so, how? If not, what happens to them?

[Stlhead]

Better call Saul.

[wgj3]

Often they get "lost" if there isn't a family member willing to pay to transfer each item. $200 for each sbr, another $200 for each supressor.

Easy way to deal with end-of-life stuff is to set up a trust. Maybe for just 1 or 2 items you don't worry about it, but a trust is cheaper than even a single transfer fee.

I have AR pistols and AR rifles. Thus, I have all the items to "build" an SBR, but I'm not doing anything wrong as long I dont pin a short upper to a lower with a stock.

[jon49erfan]

Often they get "lost" if there isn't a family member willing to pay to transfer each item. $200 for each sbr, another $200 for each supressor.

When someone dies, they get transfered tax free on a form 5.

[MJN1957]

5. NFA firearm ownership can be idiosyncratic. They are NOT treated like 'standard' firearms in several important ways.

Yes, please expand if you have time. knowledge is power.

Also, what happens when people pass away with NFA stamps/rifles? Can they be passed onto family members? if so, how? If not, what happens to them?

A key difference between certain NFA firearms and "conventional" (non-NFA) firearms is how the serial-numbered part is treated.

Like 'conventional' firearms where a firearm originally built as a rifle is always a rifle and a pistol is always a pistol, machine guns are always machine guns. SBRs (and SBSs) are treated differently, however.

With a 'conventional' firearm, the serial-numbered part is the firearm for all intents and purposes. You can change any other part, or sell every part but the bare receiver and - from a legal perspective - you still have the same firearm you initially purchased. Not so with SBRs.

SBRs are a NFA-regulated 'configuration' of a conventional firearm type. If you change that configuration to one that is not regulated by the NFA, and no longer possess the parts necessary to change it back to the NFA-regulated configuration, the firearm is no longer a NFA-regulated firearm and it can be possessed, transported, given, or sold just like any other conventional firearm.

This is always a controversial statement, but there is no such thing as a "registered receiver". It is a term a lot of people use, but it isn't accurate.

When an application (the Form 1) is filed with the BATFE to build a SBR, it is best viewed as asking for permission to build the SBR. On that application, you have to provide a serial number for the SBR you will be building. If you use an existing serial-numbered receiver to build your SBR, you must use the serial number on that receiver. If you are making your own receiver - say completing an 80% receiver or doing a custom receiver - you put the serial number you intend to put on that completed receiver. Once your application is approved and the tax stamp issued, like previously noted, you then have permission to build a firearm in the approved configuration (in this case, a SBR).

In effect you are not 'registering a receiver', you are registering a serial number and that is an important distinction.

There are two key requirements once you receive permission to build a NFA-regulated firearm. One: if you build the NFA-regulated firearm identified on your approved application, it must be built in the approved configuration (example: you can not apply to build a SBR then build a SBS). Two: when it is in the approved NFA-regulated configuration, it must bear the serial number that was supplied on your application.

Since you are registering a serial number - not a 'receiver' - there are several advantages.

If you travel with your SBR, you must have prior permission from the BATFE to transport it across state lines (just like machine guns and SBSs). It is a perfunctory request (Form 5320.20) and you can get permission for up to a year at a time to cover numerous interstate trips to the same state (each state requires a separate Form 5320.20). You can also change the configuration to a non-regulated one, however - with an AR, just change the upper to one with 16" or longer barrel - and once you no longer have possession of the parts necessary to change the configuration back to a SBR - say, you leave the SBR upper in your safe at home - it is treated like a conventional firearm. As a conventional firearm it can be transported anywhere the firearm is legal without permission from the BATFE (because it is not a NFA-firearm at that point, registered serial number or not)

Another advantage is that you can permanently remove the firearm from the NFA Registry at will. If, for whatever reason, you permanently dispose of the parts necessary to configure your SBR ( e.g., you sell your only SBR upper) and do not intend to create that configuration again, the firearm is instantly no longer a NFA-regulated firearm and it can be possessed, transported, given, or sold as a conventional firearm. The BATFE requests a courtesy notification if you intend to permanently remove the firearm from the NFA Registry, but it is NOT required. In fact, it is generally recommended that you not since you may want to make it a SBR again (and if you have formally remove it from the registry, you will need to file another Form 1, and pay $200 again before you can).

Also, once you have an approved Form 1 you can choose to NOT build the approved firearm and you can get your $200 back. Just be sure that you have not possessed all of the parts necessary to build a SBR (the short barrel, basically), and that you sure as heck haven't actually BUILT it, and you can get your tax payment refunded with a routine request.

There are some other minor differences between conventional firearms and NFA-firearms, but those are the ones most people considering them aren't aware of.

Enjoy your SBR when you build it. They are a blast in more ways than one! Just make sure everyone else nearby has good hearing protection when you shoot it!

MikeN

Edited December 30, 2015 by MJN1957

[GregSmith]

Fantastic information. Thank you!

G