[bruoz]

Well having converted many firearms to full auto with registered drop in auto sears back in the day, not to mention slotted UZI bolts, it is the function of recoiling gun parts (or the whole gun in the case of bump stocks)that causes full auto capability. The part of the law that is relevant is that you are modifying the gun to fire more than one shot when the trigger is pulled. Whether you hold the stock tight for semi or loose for full auto is the same as changing a selector which can be easily demonstrated.

[old-ager]

> you are modifying the gun to fire more than one shot when the trigger is pulled

with bump stock each pull results in one shot. one shot per function of the trigger. you know that.

[afterhoursarmory]

I believe you are incorrect there. Even holding it “loose” it is still one shot per one trigger pull. Completely different from a sear.

[suthener]

"The part of the law that is relevant is that you are modifying the gun to fire more than one shot when the trigger is pulled." This is what the ATF originally said about bump stocks: “Since your device does not initiate an automatic firing cycle by a single function of the trigger,” Curtis said, “FTISB finds that it is NOT a machinegun under the [National Firearms Act], or the amended [Gun Control Act].” Unless you know more that the ATF’s Firearms Technology Industry Services Branch your conclusion is simply wrong.