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evollep3
08-31-2009, 9:40 PM
can you put a BMG upper on a 80% lower?

aplinker
08-31-2009, 9:58 PM
Sure, as long as the 80% "hunk of metal"/lower remains a non-rifle forever.

It doesn't matter where the rifle comes from, you can't have an unregistered .50BMG rifle.

The upper is legal. Would be fine for a pistol (yikes) or a spade-gripped gun.

Josh3239
08-31-2009, 10:02 PM
Would be fine for a pistol (yikes)

Are you sure? I am pretty sure that would make it a DD.

tommyid1
08-31-2009, 10:08 PM
hmmm 50 bmg pistol... :21:

EBR Works
08-31-2009, 10:42 PM
Like this one?

http://www.google.com/imgres?imgurl=http://airbornecombatengineer.typepad.com/photos/weapons_fireams/thunder50diagonalace.jpg&imgrefurl=http://airbornecombatengineer.typepad.com/airborne_combat_engineer/2005/01/the_thunder_50_.html&h=313&w=460&sz=31&tbnid=AFkswHXvlTDNRM:&tbnh=87&tbnw=128&prev=/images%3Fq%3D50%2Bbmg%2Bpistol&hl=en&usg=__VEwvwM-f6yFkWY_hECGOEdYmsVw=&ei=67OcSqz6I5-qtgeNnsDJBA&sa=X&oi=image_result&resnum=2&ct=image

http://airbornecombatengineer.typepad.com/photos/weapons_fireams/thunder50tripleactionllcloganut.jpg

It would be legal since only .50 BMG rifles are banned.

evollep3
08-31-2009, 11:16 PM
Sure, as long as the 80% "hunk of metal"/lower remains a non-rifle forever.

It doesn't matter where the rifle comes from, you can't have an unregistered .50BMG rifle.

The upper is legal. Would be fine for a pistol (yikes) or a spade-gripped gun.

that is what i thought until someone made me question myself so i had to verify to make sure im not insane but than again every time i get bored i go build another rifle :(
example:
http://i44.photobucket.com/albums/f49/Evollep3/IMG_0936.jpg
that was today just done

Josh3239
08-31-2009, 11:17 PM
deleted

leelaw
09-01-2009, 12:45 AM
Like this one?

http://www.google.com/imgres?imgurl=http://airbornecombatengineer.typepad.com/photos/weapons_fireams/thunder50diagonalace.jpg&imgrefurl=http://airbornecombatengineer.typepad.com/airborne_combat_engineer/2005/01/the_thunder_50_.html&h=313&w=460&sz=31&tbnid=AFkswHXvlTDNRM:&tbnh=87&tbnw=128&prev=/images%3Fq%3D50%2Bbmg%2Bpistol&hl=en&usg=__VEwvwM-f6yFkWY_hECGOEdYmsVw=&ei=67OcSqz6I5-qtgeNnsDJBA&sa=X&oi=image_result&resnum=2&ct=image

http://airbornecombatengineer.typepad.com/photos/weapons_fireams/thunder50tripleactionllcloganut.jpg

It would be legal since only .50 BMG rifles are banned.

.50BMG as a pistol is a destructive device, due to the manner in which the Feds measure the diameter (grooves on pistol, vs. lands on rifle) of the round, which makes the .50BMG in excess of .50 inch, and thus a destructive device.

ke6guj
09-01-2009, 12:57 AM
leelaw, have you seen any specific info that specifies that they measure the bore differently between handguns and rifles?

I saw something recently about how that came up with the Desert Eagle .50AE, but it was mentioned that the DE50 has a polygonal barrel, so a .50" rod would fit in the barrel, whereas a standard barrel shooting the same .51" bullet would not let the .50" rod slide freely into it. DE then retooled to shoot a .50" bullet with a barrel that would not allow for the .50" rod to slide in.

I'm wondering if the polygonal issue is where the issue was instead of handguns and rifles being measured differently?

EBR Works
09-01-2009, 7:18 AM
.50BMG as a pistol is a destructive device, due to the manner in which the Feds measure the diameter (grooves on pistol, vs. lands on rifle) of the round, which makes the .50BMG in excess of .50 inch, and thus a destructive device.

Didn't know that. Thanks for the clarification.

leelaw
09-01-2009, 9:27 AM
leelaw, have you seen any specific info that specifies that they measure the bore differently between handguns and rifles?

I saw something recently about how that came up with the Desert Eagle .50AE, but it was mentioned that the DE50 has a polygonal barrel, so a .50" rod would fit in the barrel, whereas a standard barrel shooting the same .51" bullet would not let the .50" rod slide freely into it. DE then retooled to shoot a .50" bullet with a barrel that would not allow for the .50" rod to slide in.

I'm wondering if the polygonal issue is where the issue was instead of handguns and rifles being measured differently?

Destructive Device (DD) (Defined NFA title 26).

"Destructive device. -- The term "destructive device" means
(1) any explosive, incendiary, or poison gas
(A) bomb,
(B) grenade,
(C) rocket having a propellant charge of more than four ounces,
(D) missile having an explosive or incendiary charge of more than one-quarter ounce,
(E) mine, or
(F) similar device;
(2) any type of weapon by whatever name known which will, or which may be readily converted to, expel a projectile by the action of an explosive or other propellant, the barrel or barrels of which have a bore of more than one-half inch in diameter, except a shotgun or shotgun shell which the Secretary finds is generally recognized as particularly suitable for sporting purposes; and
(3) any combination of parts either designed or intended for use in converting any device into a destructive device as defined in subparagraphs (1) and (2) and from which a destructive device may be readily assembled.

The term "destructive device" shall not include any device which is neither designed nor redesigned for use as a weapon; any device, although originally designed for use as a weapon, which is redesigned for use as a signaling, pyrotechnic, line throwing, safety, or similar device; surplus ordnance sold, loaned, or given by the Secretary of the Army pursuant to the provisions of section 4684(2), 4685, or 4686 of title 10 of the United States Code; or any other device which the Secretary finds is not likely to be used as a weapon, or is an antique or is a rifle which the owner intends to use solely for sporting purposes."

BATFE has interpreted that to be a measure of lands for rifles, grooves for pistols. Here's one of the more well known stories about this interpretation:

http://www.findarticles.com/p/articles/mi_m0BQY/is_8_51/ai_n14694946

ke6guj
09-01-2009, 11:41 AM
BATFE has interpreted that to be a measure of lands for rifles, grooves for pistols. Here's one of the more well known stories about this interpretation:

http://www.findarticles.com/p/articles/mi_m0BQY/is_8_51/ai_n14694946I've heard the lands vs. grooves arguement for years, ever since the DE 50 was originally delayed because of the DD issue. I've just never seen the actual BATFE interpretation in print anywhere. But recently I've started hearing about the issue actually was caused due to the polygonal rifling causing the minor diameter of the barrel to be larger than a comprable barrel tht had conventional rifling.

A couple examples of the arguement, the first from wikipedia (I know),

The actual cartridge has a .547 inch (13.9 mm) diameter base, with a rebated rim. The rim diameter of the .50 AE is the same as the .44 Remington Magnum cartridge for which the pistol was already chambered, consequently only a barrel and magazine change is required to convert a .44 Desert Eagle to the larger, more powerful .50 AE. Original blueprints had been to use .510" diameter rounds (like the .50 BMG), but the polygonal rifling of the final prototype Desert Eagle allowed the .50 caliber bore plug to drop through, thus rendering the gun a destructive device under Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) regulations (this no longer applies on current models). Nominal bullet diameter was reduced to the current 0.500 inch (12.7 mm).http://en.wikipedia.org/wiki/.50_Action_Express


When Whilden first designed the .50AE, it used .510" bullets like the .50 BMG. It was originally a straight-walled case. However, production Desert Eagles were made with polygonal rifling, instead of L&G like the prototype. A poly rifled bore that will accomodate .510" bullets allows the DD bore gauge to fall through. Thus, the cartridge was redesigned, given a body taper to accept .500" bullets.

DD is determined by whether or not the gauge falls through. Has nothing to do with diameter of a fired bullet.
http://www.thehighroad.org/showpost.php?p=3987354&postcount=26


And the most telling example, the .500 Linebaugh uses .512" bullets, http://www.customsixguns.com/pricing.htm . SO, maybe he has a DD exemption, which hasn't been mentioned, or it may be that the DD gauge doesn't fall through and that is the determinator.

Jpach
09-01-2009, 12:24 PM
You could slap a .50 BMG upper on a complete lower that was built as a title 1 non-rifle long arm. I still gata get my lower for that project...