Replacing permanent flash hider

cannonfire · October 1, 2010, 08:25 AM

I tried to search this but I didn't find exactly what I was looking for, so if there is another thread that answers my question, please show me.

I was looking at BCM uppers with 14.5" barrels but had a permanent flash hider that put the barrel at 16.1" thus making it legal.

I know it is on there permanently for a reason, but lets say you wanted get a different one to replace it. I was reading in another thread that the ATF recognizes think its called "Silver Soder" as a way to install a flash hider where it is considered permanent, not "soft Soder", that isn't permanent enough.

So what I'm asking is, once you cut off that initial flash hider, the weapon is now a short barrel rifle, making illegal with out a stamp, but you are immediately fastening another flash hider that would put it over 16". Since you are making it an SBR first, I don't see how it would be legal to switch out flash hiders.

Is there a method to use? Do you have to go to certified gunsmiths to do it? Is it just plain out illegal and you can not permanently switch flash hiders?

*Note I have no intentions of doing this at all. I'm just curious and thought it would make a good discussion.

**44 AMP** · October 1, 2010, 10:53 AM

I'm not a laywer, so my advice is worth what you pay for it, but to me, the obvious answer is simply not to have the short barrel rifle in your posession at any time.

Send only the upper to the smith, let him do the work, and send it back to you. Without you having the parts needed to make a SBR in your posession, how can you be breaking the law?

Shorter than legal rifle length uppers, by themselves are simply parts. You can own an 11" barrel upper without any license, you can have it mailed directly to you. ITs just a few parts. BUT, if you have any lower receiver to put it on, then you are in posession of an SBR (assembled or not), and are violating the law, without first getting BATF approval.

HiBC · October 2, 2010, 02:15 PM

I was building a parts kit rifle during the Clintonian era.I wanted to be squeaky clean legal,and I ended up talking with a gentleman at the BATF Office of Firearms Technology.What he told me:Acceptable methods were a hard silver solder,there is a minimum melt temp.I do not recall what it wasbut it is well over 1000deg f.The lower temp hard solders did not make it.
You could also 360 full bead weld it on,or use the blind pin method.The BATF definition of a blind pin,pin it,then weld over the pin,then dress and finish it so the pin is not detectable.
IMO,all of these methods subject the bore at the crown to abuse which may compromise accuracy.I would think you are stuck with whatever gas block and barrel nut ison there at assembly,which would preclude changing to a free float forend.
You do whatever makes you happy,but I dont want a permanent pickle.

kozak6 · October 3, 2010, 08:07 PM

Quote:

I was building a parts kit rifle during the Clintonian era.I wanted to be squeaky clean legal,and I ended up talking with a gentleman at the BATF Office of Firearms Technology.What he told me:Acceptable methods were a hard silver solder,there is a minimum melt temp.I do not recall what it wasbut it is well over 1000deg f.The lower temp hard solders did not make it.
You could also 360 full bead weld it on,or use the blind pin method.The BATF definition of a blind pin,pin it,then weld over the pin,then dress and finish it so the pin is not detectable.

Straight from the horse's mouth:
Page 2 (pdf 1.6 mb)
http://www.atf.gov/publications/down...-chapter-2.pdf

October 1, 2010, 10:53 AM	#2
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,833	I'm not a laywer, so my advice is worth what you pay for it, but to me, the obvious answer is simply not to have the short barrel rifle in your posession at any time. Send only the upper to the smith, let him do the work, and send it back to you. Without you having the parts needed to make a SBR in your posession, how can you be breaking the law? Shorter than legal rifle length uppers, by themselves are simply parts. You can own an 11" barrel upper without any license, you can have it mailed directly to you. ITs just a few parts. BUT, if you have any lower receiver to put it on, then you are in posession of an SBR (assembled or not), and are violating the law, without first getting BATF approval. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

October 2, 2010, 02:15 PM	#3
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,286	I was building a parts kit rifle during the Clintonian era.I wanted to be squeaky clean legal,and I ended up talking with a gentleman at the BATF Office of Firearms Technology.What he told me:Acceptable methods were a hard silver solder,there is a minimum melt temp.I do not recall what it wasbut it is well over 1000deg f.The lower temp hard solders did not make it. You could also 360 full bead weld it on,or use the blind pin method.The BATF definition of a blind pin,pin it,then weld over the pin,then dress and finish it so the pin is not detectable. IMO,all of these methods subject the bore at the crown to abuse which may compromise accuracy.I would think you are stuck with whatever gas block and barrel nut ison there at assembly,which would preclude changing to a free float forend. You do whatever makes you happy,but I dont want a permanent pickle.