OSD 344: The ATF shot itself in the foot with Franklin Armory’s new gun
Under US law, a short-barreled rifle is “a rifle having one or more barrels less than sixteen inches in length and any weapon made from a rifle (whether by alteration, modification, or otherwise) if such weapon, as modified, has an overall length of less than twenty-six inches”.
Ok, and what is a rifle? It is (emphasis added) “a weapon designed or redesigned, made or remade, and intended to be fired from the shoulder and designed or redesigned and made or remade to use the energy of an explosive to fire only a single projectile through a rifled bore for each single pull of the trigger”.
Last Thursday, the mad scientists at Franklin Armory launched the Antithesis. It is, as far as we can tell, a bog-standard AR-15 that comes in 7.5-12.5” barrel configurations.
One day later, Franklin Armory pulled the Antithesis off their site under threat from the ATF. Here’s what happened.
Franklin Armory noticed the bold section in the definition of “rifle” above. They built an Antithesis that, like well-known combination guns such as the Taurus Judge, fires both .45 Long Colt ammo and .410 shot shells. They argued that because the shot shells contain multiple projectiles, the Antithesis is not a rifle. Therefore it can’t be a short-barreled rifle and isn’t subject to NFA regulation. After lengthy litigation, the ATF issued a letter this August agreeing with Franklin Armory’s contention that the Antithesis isn’t an SBR.
Two weeks and change after that letter, Franklin Armory announced the Antithesis in 5.56mm, for sale immediately. Turns out they had secretly designed a 5.56mm duplex round, and were now arguing that because that consists of multiple projectiles, the same logic that made the .45LC/.410 Antithesis a not-SBR also makes the 5.56mm Antithesis a not-SBR.
Logically sound, but what is the purpose of government if not to insert illogic where it shouldn’t be inserted. So the ATF issued a new statement saying that their previous letter “only applies to the two models listed in the letter, in the specific configuration that was the subject of the settlement agreement”.
In the short term, that’s a loss for Franklin Armory. But it’s one they led the ATF into on purpose. Franklin Armory have been doing this long enough to know that federal agencies keep their determination letters as narrow as possible. No agency will voluntary let you extend the meaning of a letter one word beyond what they wrote. No other examples, no extrapolation.
That’s especially true in this case. Any rifle can fire duplex ammo. So if being “designed or intended” to fire duplex ammo means a gun is not an SBR, then no gun is an SBR. The ATF endorsing that position is the bureaucratic equivalent to turkeys voting for Thanksgiving. They won’t do it.
Except they already did. They’re on record that an AR that can fire a multi-projectile round isn’t an SBR. Franklin Armory is just applying that logic consistently, and the ATF has two choices:
Rule that all ARs are not-SBRs.
Dig the hole deeper, and go through contortions to explain why the law doesn’t mean what the words in the law plainly say.
Franklin Armory probably engineered this whole thing to force the ATF into option 2. That’s clever in the current political environment.
Someone on X pointed out the similarities here to a 2019 case where the ATF dropped charges against someone they’d caught illegally manufacturing and selling AR-15s. The judge in that case gave prosecutors a heads up that he was going to rule that AR-15 lowers are not firearm receivers, because the law defines a receiver as “that part of a firearm which provides housing for the hammer, bolt or breechblock, and firing mechanism, and which is usually threaded at its forward portion to receive the barrel”. AR-15 lowers don’t meet that definition and so can’t be regulated as firearms. The ATF dropped the charges rather than let the judge issue a final ruling and set that precedent.
The general lesson here is that federal gun law is ancient. It’s built on a foundation of rules from 1934 and 1968. Guns are evolving faster than the laws are. Over time, that will work like a slow-motion repeal.
We’ll leave you with two comments on this from our Discord subscribers.
Hoffnung:
An idea i’ve brought up a lot is the tendency for gun restrictionists, fudds, and restrictive states to hone in on the idea that “a Normal Gun is OK, accessories and specialized weapons are Haram”. This meanwhile, and significantly for this case, very much ties into a failure to appreciate how 1. modern guns are ultra-modular and 2. the endless variety of unusual concepts that will be tried, especially but not exclusively as a deliberate loophole-seeking process but also one to structurally make very strict laws hard to enforce.
cbrumbaugh:
ATF: You intend to turn this chunk of raw aluminum into a suppressor ergo it is already a suppressor
Franklin: This is not a rifle because it was designed with the intent of firing duplex projectiles
ATF: Incoherent screaming
This week’s links
James May at a gun range
Notable that ten years ago, this video would have been produced to make the experience seem like an extreme sport. Today it’s shot as a low-key outing for friends. Normalization.
Everytown has shooting courses now
Genuinely good that they’re doing this. H/t Discord subscriber Analogy.
“Opposition to the 2nd Amendment in the Late 21st Century”
Speculative future gun culture.
About Open Source Defense
OSD Capital
We invest in civilian defense and all adjacent tech. Our mission: increase freedom, self-determination, and decentralization. Reach out.
OSD podcast
In-depth interviews with outstanding founders and builders in the civilian defense industry.
The company store
Grab a t-shirt or a sticker.
Discord server
The OSD team is there along with lots of subscribers. Become a paid Substack subscriber to join the chat.


Everytown is pulling the old wolf in sheep's clothing act. No way in hell does a fusion group of Bloomberg and Moms Demand offer anything remotely reasonable. I imagine the training begins with "guns are evil," progresses to an "only extremists own firearms," and then finishes off with a combined rendition of both of the former to top everything off.