.25 ACP can

[fishman]

Is it your position that firing a projectile greater than .22 Caliber through a suppressor marked ".22" constitutes a de facto felony, even without any physical changes being made to the suppressor

. No, I have no idea how the ATF feels about that.

What they specifically dont allow, is modifying an existing silencer to change its caliber. This is, according to them, making a new silencer.

In regards to your bullet diameter and caliber discussion: caliber is defined as bore diameter, not projectile diameter. A 223 is 22 caliber. A 22LR is 22 caliber. A 25 acp is 25 caliber. Modifying the silencer to change its caliber is what the ATF frowns upon. I have no idea why. The actual written law says nothing about caliber.

[Prince Yamato]

Here is the actual language from the atf handbook:
—-
Q5: May a repair change the dimensions or caliber of a silencer?
A: If alterations to a silencer would increase the overall length or change the diameter or caliber of a silencer, this is the making of a new silencer, as opposed to a repair. The new silencer must be registered and transferred in accordance with the NFA and the GCA. Alterations to a registered silencer that result in a minimal reduction in the overall length for purposes of rethreading are permissible as...

However, the reduction in length may not result in the removal, obliteration, or alteration of the existing serial number, as this would violate 18 U.S.C. § 922(k). If such a repair is necessary, the damaged silencer should be destroyed or returned to the registrant. If it is destroyed, destruction should be reported to the NFA Branch. Any replacement silencer must be registered and transferred in accordance with the NFA and the GCA. See Q2 and Q3 for further information on repairs.
—-

My guess is that if you shot a slightly larger caliber through a can smaller than the caliber listed (due to baffle holes accommodating), it would be “misuse,” kind of like shouldering an arm brace.

If you sent can to be bored out from .2xx caliber to .3xx or .4xx, or you had an FFL replace with a baffle stack and endcap meant for a larger caliber, that would be an obvious caliber change. I think the spirit of the law is in the same vein as those guys who were cutting S/N off of Mac-10s and putting them on new RPKs and then submitting caliber and barrel length changes to the ATF.

Shooting .25 out of a .22 can is not suspicious. If all of a sudden you put your .22 can on the end of a .338 lapua sniper rifle, then I might raise an eyebrow.

I think the first question that the atf asks itself is: “is this person skipping out on giving me my $200?”

The second question is: “will fighting this person in court, help or hurt the atf as an organization?”

[Prince Yamato]

To add...

The reason NFA laws always seem unclear is that the NFA was written almost 90 years ago. That’s pre AR-15, multi-cal silencers, and pistol braces. It was written by politicians who (much like today) thought they knew everything. The clearest parts of it (the machine gun part, which was the principal focus) are the easiest to interpret. The other parts were clearly the afterthoughts.

[ECCO Machine]

If you sent can to be bored out from .2xx caliber to .3xx or .4xx, or you had an FFL replace with a baffle stack and endcap meant for a larger caliber, that would be an obvious caliber change.

Whether or not it's legal to increase the size of the bore through a suppressor without a new F1 depends on the reason you give for doing it.

To shoot larger calibers? Nope.

To reduce back pressure or mitigate concerns over baffle & cap strikes? Perfectly legal.

I make 5.56 cans with a 300" bore, and .30 cal cans going on AKs get a .420" bore. I've also put .500" bores in 9mm cans to reduce port pop. There is no maximum suppressor bore size for a given caliber, only a minimum. You can't have can designated .30 cal with a .29" bore, but if it's .49", no problem. They must be able to pass bullets of the listed caliber; if they can pass larger ones, it is incidental.

[Capt. Link.]

The bore size of the suppressor has nothing to do with the legality of using a larger caliber than listed, its the intent of use that is in question.

If you wish to err on the side of legality list the actual bore size. Many .22LR cans have a .280 bore so technically the use of 7mm on down is no problem if you list the bore diameter.

Prince Yamato if it has not been said any .22LR suppressor design will work just fine for .25 ACP.
.251+.060=.311 or .303 British on down.
-CL

[fishman]

Recommending it to people online simply because the ATF didnt define what constitutes a caliber change is irresponsible. If you want to do it and see if the loophole holds in court, by all means, go ahead. Dont tell other people its perfectly legal.

You still haven't answer my question about how you legally changed silencer calibers without a second stamp.

As far as legally changing caliber, read your form 1. Just send an amendment letter.The

I just read through the current form 1 online. I cant find any information about this. As far as form amendments go, it was my understanding that caliber or length of a silencer can be amended BEFORE the silencer is completed, not after. I have no source on the legality of this other than second hand experience.