How to legally build a Short Barreled Shotgun (SBS)

BlenderWizard · **Posted:** Wed Aug 30, 2006 8:37 pm

Banshee wrote:

BlenderWizard wrote:

So, what's the easiest way to cut down the mag tube and rethread it?

I used a lathe and a 4 Jaw chuck to do mine.

the Magazine tube has a 1 inch 12 square thread.

and the fore-end has a 1.080 inch-32 thread

So, it's like a pipe threading machine?

Banshee · **Posted:** Wed Aug 30, 2006 9:50 pm

BlenderWizard wrote:

Banshee wrote:

BlenderWizard wrote:

So, what's the easiest way to cut down the mag tube and rethread it?

I used a lathe and a 4 Jaw chuck to do mine.

the Magazine tube has a 1 inch 12 square thread.

and the fore-end has a 1.080 inch-32 thread

So, it's like a pipe threading machine?

not quite. I used a machine similar to this one

http://www.nsmachine.com/11294_1.jpg
http://www.nsmachine.com/11294_2.jpg

Banshee · **Posted:** Wed Aug 30, 2006 9:57 pm

BradN wrote:

How did you hold the magazine tube to thread it? I want to do mine one day but before I send off my paper work, I want to make sure I can do it myself. I've been racking my head over how to hold it in the lathe

Thanks
Brad

you need a machine with a large enough 4 jaw chuck to hold the receiver. Support the mag tube with a snug fitting brass plug held in the tailstock.

BradN · **Joined:** Wed Aug 30, 2006 6:23 pm **Posts:** 18

cool, I think my biggest challenge is that my lathe is a bit short for the job at hand. One of the ways I wanted to do it was to keep my Mesa AR15 stock adapter on it, since the bore of the stock is parallel to the magazine tube. Machine a stub to go into the stock mount and hold that in the 4 jaw chuck. With all this, the lathe is too short to cut it down to 3 rounds. Might work for 2 rounds like your gun though, didn't look into that route.

I'll take another look tomorrow and see if the chuck is big enough to hold the receiver itself.

Thanks for the tips.
Brad

Banshee · **Posted:** Wed Aug 30, 2006 10:18 pm

I would put small alum blocks between the chuck jaws and the Receiver so it won't get damaged.

BradN · **Joined:** Wed Aug 30, 2006 6:23 pm **Posts:** 18

Got some brass ones I use for stuff like this, so I should be safe.

hmm....this is getting interesting now.
Thanks
Brad

Banshee · **Posted:** Wed Aug 30, 2006 10:28 pm

just don't cut the barrel untill you get your forum 1 back..

BradN · **Joined:** Wed Aug 30, 2006 6:23 pm **Posts:** 18

Oh yes...I know.
Plan was to cut the magazine back, thread it, then move the collar on the barrel back, leaving it 18" still. Once I get the form back, then hack it off and true it up.

I found the action bar off of a Special Field model on gunbroker.com so I don't have to rethread that, but now I might go shorter, 2 rounds.

B

BlenderWizard · **Posted:** Thu Aug 31, 2006 7:43 am

Banshee wrote:

BlenderWizard wrote:

Banshee wrote:

BlenderWizard wrote:

So, what's the easiest way to cut down the mag tube and rethread it?

I used a lathe and a 4 Jaw chuck to do mine.

the Magazine tube has a 1 inch 12 square thread.

and the fore-end has a 1.080 inch-32 thread

So, it's like a pipe threading machine?

not quite. I used a machine similar to this one

http://www.nsmachine.com/11294_1.jpg
http://www.nsmachine.com/11294_2.jpg

Is the machine yours? Where did you get access to something like that?

Banshee · **Posted:** Thu Aug 31, 2006 10:45 am

no,I don't own a lathe. I found that for sell on the web. I have been thinking about buying one. Not a bad price $6500. I work in a large machine shop.

BlenderWizard · **Posted:** Thu Aug 31, 2006 12:26 pm

Banshee wrote:

no,I don't own a lathe. I found that for sell on the web. I have been thinking about buying one. Not a bad price $6500. I work in a large machine shop.

Ahhh! you machine shop guys are killing me. I'd love to work in a machine shop, and I've got experience on a CNC lathe and CNC mill, but there doesn't seem to be any shops nearby...

Banshee · **Posted:** Thu Aug 31, 2006 10:10 pm

we can use company tools on our own time. It is handy having a complete machine shop anytime you need it. It is open 24 hours aday 7 days a week

BradN · **Joined:** Wed Aug 30, 2006 6:23 pm **Posts:** 18

I can see the bossman walking around the corner and seeing you working on it.

"what are you doing?"
"shortening the magazine tube and barrel on my shotgun."
"uh...clean up when you are done."

yuuts · **Posted:** Sat Sep 02, 2006 11:20 pm

Banshee wrote:

ALWAYS keep a copy of the approved form with the gun. You can travel anywhere with in your state without notifying anyone, (the same has a normal firearm) If you want to take it to another state, you MUST FIRST, notify the ATF with a form 5320.20 Application to Transport Interstate or to Temporarily Export Certain National Firearms Act (NFA) Firearms. This is tax free, and you can do it by FAX.. you can download from the same website as the others or use this direct link.

I had no idea about the notification part, thanks. It doesn't apply to sound supressors (my little area of Class III). And thanks for helping me to want yet ANOTHER toy. I'm telling my wife it's all your fault!

jediagh · **Joined:** Fri Sep 16, 2005 9:34 pm **Posts:** 268

What agency would know if SBS are allowed in my state?

BradN · **Joined:** Wed Aug 30, 2006 6:23 pm **Posts:** 18

Here you go
http://www.mp5.net/info/sbsconr.htm

Banshee · **Posted:** Mon Sep 11, 2006 5:21 pm

yuuts wrote:

Banshee wrote:

ALWAYS keep a copy of the approved form with the gun. You can travel anywhere with in your state without notifying anyone, (the same has a normal firearm) If you want to take it to another state, you MUST FIRST, notify the ATF with a form 5320.20 Application to Transport Interstate or to Temporarily Export Certain National Firearms Act (NFA) Firearms. This is tax free, and you can do it by FAX.. you can download from the same website as the others or use this direct link.

I had no idea about the notification part, thanks. It doesn't apply to sound supressors (my little area of Class III). And thanks for helping me to want yet ANOTHER toy. I'm telling my wife it's all your fault!

suppressors and AOWs doesn't need a 5320.20 to transport across state lines.

Banshee · **Posted:** Mon Sep 11, 2006 5:26 pm

BradN wrote:

I can see the bossman walking around the corner and seeing you working on it.

"what are you doing?"
"shortening the magazine tube and barrel on my shotgun."
"uh...clean up when you are done."

I do my all personal work after hours, and only take the part that I need to modifiy.

77XLH · **Posted:** Tue Sep 12, 2006 12:34 pm

BradN wrote:

Here you go
http://www.mp5.net/info/sbsconr.htm

One more reason why Illinois sucks.

Grizzlywinmag · **Joined:** Sat Sep 27, 2003 12:43 am **Posts:** 4958

Because I can never remember the legal cite for this info, I'm posting it here for convenience. It's somewhat on topic, too.

HOW TO MEASURE A SHOTGUN FOR LEGAL MINIMUM LENGTH

27 CFR 479.11

"For purposes of this definition, the length of the barrel having an integral chamber(s) on a shotgun or rifle shall be determined by measuring the distance between the muzzle and the face of
the bolt, breech, or breech block when closed and when the shotgun or rifle is cocked. The overall length of a weapon made from a shotgun or rifle is the distance between the extreme ends of the weapon measured along a line parallel to the center line of the bore."

http://edocket.access.gpo.gov/cfr_2006/ ... 479.11.htm

viewtopic.php?f=7&t=80131&p=671336#p671336

How to legally build a Short Barreled Shotgun (SBS)

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