New guy with a bunch of questions

[javaduke]

Hi there, I just joined this forum seeking for wisdom I'm not new to firearms and gunsmithing, but very new to suppressors and suppressor making. As my first build, I will go for a rimfire can from a fuel filter kit from here: https://www.banggood.com/11pcs-Blue-Fue ... rehouse=CN
(yes, I know it's not ideal, but just as a first build which I'm not afraid to screw up, it should do). I spent a lot of time reading posts on this forum but still have a few questions:

1. Is it legal to have *UNDRILLED/UNFINISHED* parts kit before my Form 1 is submitted?
2. Do I have to engrave the NFA markings on the tube before I finish drilling the baffles? Or can it be done after?
3. I can't find much information on baffle design - seems like ATF doesn't like people publishing step-by-step tutorials and/or blueprints. I've seen pictures of baffles with a hole/opening on the side in addition to the center hole, but could not quite understand what is the purpose of it and if it is necessary for a rimfire can.
4. I'm planning to clamp a 4-jaw chuck on my milling machine table and use a drill bit and an end mill to drill the baffle holes, so it should be fairly concentric. Are there any other things besides holes size and concentricity that I should be concerned about?
5. Forgot to ask one important question - do I *HAVE* to submit any photos or design sketch to ATF when I submit an eForm1? I don't really have any.

Sorry if any of these are FAQ, and many thanks in advance for any help!

JavaDuke

[a_canadian]

1. Probably legal, but why risk having to get a lawyer and defend yourself? Why not wait to have the documentation in hand before you start making baffles, or order a 'solvent trap' sort of kit? Waiting would seem prudent.

2. I've seen a lot of folks do the engraving after doing everything else except applying whatever finish to the can, but don't know the specific legality involved.

3. Read a lot of threads here. The 'completed builds' thread is long, has many links to long discussions with pictures showing various people's suppressors, some even with videos.
viewtopic.php?t=79895

4. Getting the holes all perfectly lined up is important, so is clearance. Too small a bore and even if you don't have contact between bullet and baffle there can be surface effects which throw accuracy out the window. Keeping the bore too small is generally a mistake - one I certainly made in building for .22lr for example, using a 0.25" hole was too small and accuracy suffered. Going to about 0.28" works just as well for suppression with a good baffle design and gets your accuracy back.

5. From what I've read in many threads it seems the ATF isn't interested in your design beyond overall length, perhaps diameter. Many have even gone so far as to say it's better to state a length which is the MAXIMUM you'll actually use, and that coming up slightly short is no legal problem. Just don't go OVER that length.

[javaduke]

Wow, thank you so much for the info! (Aren't Canadians the nicest people in the world? ))
So the only question remains is about the baffle design. I just saw a post on TFB about the new commercial rimfire suppressor at https://www.thefirearmblog.com/blog/201 ... uppressor/ and the first picture shows baffles with a side cutout as well as the half-circle clipping at the top. I guess I can try to replicate this design.

[a_canadian]

Huh, hadn't seen that modification to a conical baffle before. Seems they've borrowed the central jet/vent feature from a K baffle and incorporated it into a cone baffle. Cool. I can't see it working quite so well on a rimfire round as a proper short K baffle, but it probably comes close. If you were doing this with pre-made cone baffles I'd suggest being careful about thickness. Griffin has obviously left the material much thicker at the pointy end of the cone to allow for the scoop, where most of the kit supplied cone baffles I've seen online don't have any extra thickness there. Milling as they've done would just open up a lopsided hole, no scoop, defeating the purpose and reducing suppression efficiency rather badly.