Educate me on the SIG serial # only on trigger assembly

[SteyrAUG]

The whole purpose of the serialized Fire Control Unit is so the rest of the components can be modular. I can own one FCU and build multiple handguns around it - grip module size and type, caliber, slide, etc. I like it that way and it is why I bought a P320.

Everyone understands the purpose, but now ATF has an entire new way to declare a fire control group to be a firearm. Pretty soon any and all parts will be declared "firearms" and that is what I object to.

[SteyrAUG]

So, you have a subcompact, compact, service size, and extra sized game sized item collection of four things.

Each of which is exactly the same size and shape as a functional handgun. But at any one time you only have one functional handgun and three non functional items.

For minimal expenses, you could have four functional handguns taking up the same size and space by putting something inside the other three.

I can’t wrap my head around why I would want to do that.

Don't blame the gimmick. HK did something similar with the HK4 back in the 60s where you just changed the barrel and magazine and had four caliber options. Nothing wrong with that, nothing wrong with the SIG idea, the problem is "fire control groups" have now qualified as a registered firearm and that isn't very good.

Not everyone is trying to be practical / tactical or whatever. And if somebody wants a handgun that can be configured in four sizes and that works for them, then the market exists. You might never own one, I might never buy one...but who cares. I own a bunch of stuff that doesn't make sense to anyone else.

[Tx_Aggie]

...the problem is "fire control groups" have now qualified as a registered firearm and that isn't very good.

This is an excellent point, and admittedly not something that had occurred to me before you mentioned it.

[austinN4]

Everyone understands the purpose, but now ATF has an entire new way to declare a fire control group to be a firearm.

Only because it is the serialized part, no?

[SteyrAUG]

Only because it is the serialized part, no?

Correct. But now it has set a precedent. What happens when barrels become considered a "firearm" by ATF because some new technology allows for a modular barrel to be changed out on a host of "frames" which should be the serial numbered part but aren't?

By the old rules, SIG should have needed to serial number each frame and the "fire control group" could still be a drop in "part" that can be walked to each frame as the owner wished. So now something "new" has been declared a "firearm" when it is just a group of parts.