Yes, it can be legal to make a silencer. For everything Form-1, from silencer designs that are easily made, to filing forms with the BATF, to 3D modeling. Remember, you must have an approved BATF Form-1 to make a silencer. All NFA laws apply.
I have been lurking this awesome forum for a while now, and absorbed lots of useful information about suppressors. I'm building a suppressor or LDC for my airgun (legal in my country!) and came up with a k-baffle design to be 3D printed.
Blast baffle will be shaped as an airstripper (not on a drawing).
Everything will fit in a 30x110mm aluminium tube with threads to screw on a air rifle.
Air rifle is .22 cal with muzzle velocity about 180 m/s ( 590 fps )
Any advise or guidance would be greatly appreciated
Are you printing each baffle separately or are you printing the whole silencer as one piece? If it's one piece, I'd print the baffles all aligned instead of alternated rotationally.
I know that 3d printing allows you to make baffles in ways that aren't possible or aren't cost effective with traditional machining. I'm curious as to what your thought process was when you deviated so far from a standard k design. Your design is less rotationally symmetrical, and shorter than typical (only 1.5cm). I'm not sure if this will help or hurt your performance.
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Just a observation but traditional K baffles split the gas flow between the coaxial space and the interior of the cone spacer.While air rifles have a different pressure curve I would preserve the division of gases the original design provides.
-CL
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
fishman wrote:Are you printing each baffle separately or are you printing the whole silencer as one piece? If it's one piece, I'd print the baffles all aligned instead of alternated rotationally.
I know that 3d printing allows you to make baffles in ways that aren't possible or aren't cost effective with traditional machining. I'm curious as to what your thought process was when you deviated so far from a standard k design. Your design is less rotationally symmetrical, and shorter than typical (only 1.5cm). I'm not sure if this will help or hurt your performance.
Capt. Link. wrote:Just a observation but traditional K baffles split the gas flow between the coaxial space and the interior of the cone spacer.While air rifles have a different pressure curve I would preserve the division of gases the original design provides.
-CL
I followed ideas for a user on this forum, on his design of a k-baffle for a PCP air rifle viewtopic.php?f=10&t=135986&sid=a8f9489 ... 16#p929013 . The respectable gunny50, suggested a "lip" in the kone section, to help contain some of the gases.
Another thing I followed, is the length of the baffle, for an air rifle, it was suggested that the length should not be greater than 0.55" and baffle cluster length no more than 6".
For a 5.5mm pellet I would suggest using a 6.5mm bore or even 7.0mm. Even if your thread/shoulder alignment on the rear plug is perfectly aligned with the bore of the rifle, the cross-bore interference with the relatively lightweight pellet can cause proximity effects if the baffle bore is too small, generating overly large groups. Staying at minimum 0.5mm away from the pellet is wise and slightly more clearance doesn't really hurt suppression.
Your K design should be sufficiently strong for a .22" pellet at that power level. I wouldn't push 3D printing plastics beyond that power level by much, else the baffles might collapse, but for 180m/s it appears your wall thicknesses are sufficient.
I've used 0.55" long K baffles in aluminum for a PCP up to 960fps in .22" with an 8" stack of K baffles. That very noisy rifle (a friend, testing his new powerful PCP with my can mounted) went from painfully loud to a sound almost identical to a sub-12fpe spring piston air rifle. There is nothing wrong with going longer than 6" total baffle length. The only problem is that chances of a baffle strike due to imperfect alignment of the tube to the bore go up dramatically with each additional inch.
a_canadian wrote:For a 5.5mm pellet I would suggest using a 6.5mm bore or even 7.0mm. Even if your thread/shoulder alignment on the rear plug is perfectly aligned with the bore of the rifle, the cross-bore interference with the relatively lightweight pellet can cause proximity effects if the baffle bore is too small, generating overly large groups. Staying at minimum 0.5mm away from the pellet is wise and slightly more clearance doesn't really hurt suppression.
Your K design should be sufficiently strong for a .22" pellet at that power level. I wouldn't push 3D printing plastics beyond that power level by much, else the baffles might collapse, but for 180m/s it appears your wall thicknesses are sufficient.
I've used 0.55" long K baffles in aluminum for a PCP up to 960fps in .22" with an 8" stack of K baffles. That very noisy rifle (a friend, testing his new powerful PCP with my can mounted) went from painfully loud to a sound almost identical to a sub-12fpe spring piston air rifle. There is nothing wrong with going longer than 6" total baffle length. The only problem is that chances of a baffle strike due to imperfect alignment of the tube to the bore go up dramatically with each additional inch.
Bigger bore - check
Yes, baffle strike is my biggest concern, 3D printed objects do warp a little bit. I'm probably just gonna drill bore hole afterwards.
I'm not sure if it's supposed to be that way however the cone angle on those baffles seems to not be anywhere near 60 degrees. Are air rifles different?
There is nothing magical about 60° cones on K baffles. In fact I found the necessarily longer baffles with that cone angle were louder than shorter K baffles with 45° cone angles on both air and rimfire. By a wide margin.
K cups when clipped are asymmetrical and will create a poi shift. Why not go with a symmetrical design and symmetrical clip that is more effective than k cups.
Such as? Because cones are louder than K baffles in airgun suppressors. So are washers and spacers. So are monocores of any type. Is there some other baffle arrangement which works better than a string of K baffles? POI shift isn't relevant since the suppressor stays in place full-time. It isn't shift if it's your zero.
a_canadian wrote:There is nothing magical about 60° cones on K baffles. In fact I found the necessarily longer baffles with that cone angle were louder than shorter K baffles with 45° cone angles on both air and rimfire. By a wide margin.
The flatter the angle the less strength you will have against collapse. Airguns will not give nearly the amount of pressure as a firearm so the angle is not as critical. Shallower angles can be made but you must have more material for strength which usually results in thicker sections in the baffle which reduces efficiency of the baffle.
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