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What Just Happened?
09-17-2008, 11:52 AM
I currently have a CMMG mid-length medcon upper (http://riflegear.com/p-327-cmmg-16-m10-mid-length-medcon-upper.aspx) and am hoping to make it into an MMG build so I can drop magazines. Last night, I tried removing the flash hider with an adjustable crescent wrench. No luck. Is there some lock-tite I need to heat up or do I need to put some more elbow grease into it?

P.S. There is a crush washer in there, if it makes an difference.

ohsmily
09-17-2008, 11:58 AM
Heat would help. Ideally, you will clamp the barrel in a barrel vise. When you do this, it will be easy to remove the muzzle devise and you won't put any undue torque on where the barrel meets the receiver. If you don't have one, place the rifle between your knees (after ensuring it is empty) and use your knees to hold the rifle straight while you torque the muzzle device off. You can also have another person hold the rifle instead of holding it with your legs. However, as I mentioned, when you do this, you are imparting torque to the barrel and potentially causing problems (but most likely you will be OK).

stphnman20
09-17-2008, 12:25 PM
Lets say you have a 14.5 barrel, and the muzzle is welded on there, can you still take it out?

PolishMike
09-17-2008, 12:26 PM
Lets say you have a 14.5 barrel, and the muzzle is welded on there, can you still take it out?


With a grinder, why not? Just make sure you dont assemble the rifle until you have something to bring it back up to 16"

BONECUTTER
09-17-2008, 12:40 PM
With a grinder, why not? Just make sure you dont assemble the rifle until you have something to bring it back up to 16"

No...dont do that...NFA laws of contructive possesion apply. If you have a AR (rifle) lower and a barrel under 16 not permanatly 16 inches you have a SBR.

Bad News.

BONECUTTER
09-17-2008, 12:43 PM
I currently have a CMMG mid-length medcon upper (http://riflegear.com/p-327-cmmg-16-m10-mid-length-medcon-upper.aspx) and am hoping to make it into an MMG build so I can drop magazines. Last night, I tried removing the flash hider with an adjustable crescent wrench. No luck. Is there some lock-tite I need to heat up or do I need to put some more elbow grease into it?

P.S. There is a crush washer in there, if it makes an difference.

Make sure your turning the right way....I have build a bunch of AR's and found myself turning the wrong way a few times on flash hider removals. Its easy to get turned around.

bwiese
09-17-2008, 12:47 PM
With a grinder, why not? Just make sure you dont assemble the rifle until you have something to bring it back up to 16"

Bulls**t. DON'T DO THIS.

Even disassembled, with the new shorty under-16" bbl (after removal of muzzle device) you could be regarded as in constructive possession of an SBR.

PolishMike
09-17-2008, 12:50 PM
Bulls**t. DON'T DO THIS.

Even disassembled, with the new shorty under-16" bbl (after removal of muzzle device) you could be regarded as in constructive possession of an SBR.


My bad-

So you cant ever change the handguards or muzzle break on a 14.5?

So if you have a pistol AR that your cleaning and happen to have an extra rifle lower you have an SBR?

bwiese
09-17-2008, 12:54 PM
My bad-

So you cant ever change the handguards or muzzle break on a 14.5?

If a muzzle device bringing the bbl up to 16" long blocks disassembly of the upper, yes.

Send your upper to a smith like Randall @ AR15Barrels and let him do the work.

if you have a pistol AR that your cleaning and happen to have an extra rifle lower you have an SBR?


No, because you have a lenity outcome there. Basically, you need to have parts/guns sufficient to have legal combinations of the parts - so that's the one exception - if you owned a legit pistol receiver or SBR receiver in addition to/in place of the rifle lower.

grammaton76
09-17-2008, 1:06 PM
Bulls**t. DON'T DO THIS.

Even disassembled, with the new shorty under-16" bbl (after removal of muzzle device) you could be regarded as in constructive possession of an SBR.

This is very true. Although if you're removing it and immediately welding a new extension back on, there shouldn't be an issue. I do recall reading something or other from ATF that doing work was acceptable as long as the work was continuous (i.e. you didn't stop working on it and then go do something else in the meantime), and the end result was indeed at legal length.

This means that you don't chop it off and pick up the next day, or go eat... don't even go to the bathroom. The old flash hider is removed and the new one goes on and is permanently affixed - one action right after the other, and you don't stop until it's all done.

If you've heard anything to the contrary, Bill, I'd love to hear it.

bwiese
09-17-2008, 1:17 PM
This is very true. Although if you're removing it and immediately welding a new extension back on, there shouldn't be an issue. I do recall reading something or other from ATF that doing work was acceptable as long as the work was continuous (i.e. you didn't stop working on it and then go do something else in the meantime), and the end result was indeed at legal length.

This means that you don't chop it off and pick up the next day, or go eat... don't even go to the bathroom. The old flash hider is removed and the new one goes on and is permanently affixed - one action right after the other, and you don't stop until it's all done.

If you've heard anything to the contrary, Bill, I'd love to hear it.

No, but I wouldn't even risk that. Remember that CA has similar CP laws without ATF guidance being relevant - even thouh the CA vs Fed SBR laws are similar with similar intent, how much is too far is way open to question.

saki302
09-17-2008, 1:53 PM
If you own a PISTOL lower, you should be okay (short barrel has a legal place to go). If not, have someone else do it!

-Dave

What Just Happened?
09-17-2008, 1:56 PM
Make sure your turning the right way....I have build a bunch of AR's and found myself turning the wrong way a few times on flash hider removals. Its easy to get turned around.

That's my next question. Are the standard threads the same as the standard threads on a screw (righty-tighty, lefty-loosey - from the top)?

BONECUTTER
09-17-2008, 2:07 PM
That's my next question. Are the standard threads the same as the standard threads on a screw (righty-tighty, lefty-loosey - from the top)?

Yup....so buttstock on ground-barrel to sky-looking down it **empty of course**(turn wrench counter-clockwise)

I ussually sit on the rifle and then do it if I don't have a vise around.

What Just Happened?
09-17-2008, 2:29 PM
Yup....so buttstock on ground-barrel to sky-looking down it **empty of course**(turn wrench counter-clockwise)

I ussually sit on the rifle and then do it if I don't have a vise around.

Thanks. The whole sitting on it is what I was planning on doing.

ar15barrels
09-17-2008, 3:06 PM
So you cant ever change the handguards or muzzle break on a 14.5?

So if you have a pistol AR that your cleaning and happen to have an extra rifle lower you have an SBR?

Possession of a legitimate pistol lower exempts you from possible SBR constructive possession.
If you don't own/possess a pistol lower, you can't remove permanent muzzle devices.

Just send it to me, I have a pistol lower. ;)

shark92651
09-17-2008, 6:22 PM
I currently have a CMMG mid-length medcon upper (http://riflegear.com/p-327-cmmg-16-m10-mid-length-medcon-upper.aspx) and am hoping to make it into an MMG build so I can drop magazines. Last night, I tried removing the flash hider with an adjustable crescent wrench. No luck. Is there some lock-tite I need to heat up or do I need to put some more elbow grease into it?

P.S. There is a crush washer in there, if it makes an difference.

Since you are in OC, just bring it by the shop and I'll take it off for you. It's probably just very tight due to the crush washer. They can be a bear to get off sometime if you are not using a vise and action block. I'm usually in the shop to do this sort of work in the evenings after 5:30 and all day Saturday.

Just so you know it is righty-tighty, lefty-loosy.

What Just Happened?
09-17-2008, 7:03 PM
Thanks for the offer. I finally got it off. It seemed the trick was to heat it up a bit.