I have an approved Form 1 stamp for a 9mm. I've changed my mind and would prefer to make a suppressor for a 300BLK and pin/weld it to a short barrel. I know people swap threaded suppressors between 9mm and 300BLK, but I'm wondering if there is a legal problem if I have a suppressor engraved for 9mm (per the Form 1) but permanently mounted to a 300BLK barrel.

As long as the bore of the suppressor is "9mm" I don't think you will have a problem. If you pinned, say, a liberty mystic 9mm to your rifle it wouldn't be a problem, so I dont see why doing the same with a form 1 9mm can would.

One more thing, the can would need to have a "permanent" length long enough to make the rifle a non SBR...so I guess a mystic wouldn't work

The acceptable bore tolerance is subjective. Do you really think the ATF is going to say why do you have a larger than what your form says? You could easily say to prevent bafflestrikes , etc.

It would be obviously dumb to have a .22 form1 and possess a can that is friendly to .45 or larger. That would be silly as ef but can anyone say the last time the ATF went after someone with a bigger bore than what they "should have" ?

That is why i think the caliber designation is merely for safety indications than legality.

My $0.02, no refunds.

If you are wanting to make the bore more like .360-375" which is more typical for 300blk but already have a stamp for 9mm, which typically have bores of .410-.420", instead of rolling with the .360-.375" (because it it over 9mm) I would ask email Ted Clutter and ask to have the approved form 1 modified from 9mm to 30cal. I don't think it will be an issue or take long to do.

c5_nc wrote:If you are wanting to make the bore more like .360-375" which is more typical for 300blk but already have a stamp for 9mm, which typically have bores of .410-.420", instead of rolling with the .360-.375" (because it it over 9mm) I would ask email Ted Clutter and ask to have the approved form 1 modified from 9mm to 30cal. I don't think it will be an issue or take long to do.

That's the route I'd prefer to go so that there's no grey area. How do I find contact information for this Ted Clutter or someone else in the BATF who can make this change?

Google is your friend

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