9mm design feedback requested
Posted: Mon May 04, 2020 8:17 pm
Hi all,
Thanks so much for all the info on here, it’s been awesome to read through so many builds. I’m waiting on my first form1 to clear and trying to prep everything in the meantime. I’d love to share my designs and limitations and see if anyone out there has thoughts on it. I don’t have access to a mill or lathe, so I bought a solvent trap kit with k baffles, they're a little bit chunky, but the finish is pretty nice. Once Form1 clears, I need drill bore, skirt vent, and face vent. I will 3d print jigs to hold a steel drill bushing to guide the bit and hold the baffle securely. This will make my end result slightly different from what is recommended on here I think. More on that below, my biggest questions in bold.
General design intent: 9mm subsonic, 8" OAL, 1.375" diameter. Bore drilled to .406" (1)too small? could go up a bit to .422". (2)Should end cap be bigger?
SDTA booster
1" SS blast chamber/spacer
1 - SS blast baffle (3)should I drill an additional 4 holes around the face? If so, any recommendations on size?
5 - AL baffles
Vent hole drilling (bits visualized by blue and purple): both operations will be done with a 3/8” drill bit.(4) Is this the right size for 9mm?
The face will no longer be flat, the drill bit will leave a pointed indentation. (5)Does anyone think this will be a deal breaker? I could fill it in with something high temp maybe…
The halfmoon vent is .375” x .22” (6)does this feel about right or is it a bit too big?
(7)There isn’t any overlap between the two operations. Is this okay?
(8)Is it worth trying to come up with some alignment system? I could drill a 1/16” hole near the edge of each baffle and run a long hardened 1/16” pin through all to maintain alignment.
Pictures below, many thanks for anyone with the time and experience to comment on this!
(note the sharp edges, I plan on softening these with the dremel)
(note that the operations do not overlap, I read once on here that they should, but wasn't sure if this was widely accepted)
(drilling jig models)
Thanks so much for all the info on here, it’s been awesome to read through so many builds. I’m waiting on my first form1 to clear and trying to prep everything in the meantime. I’d love to share my designs and limitations and see if anyone out there has thoughts on it. I don’t have access to a mill or lathe, so I bought a solvent trap kit with k baffles, they're a little bit chunky, but the finish is pretty nice. Once Form1 clears, I need drill bore, skirt vent, and face vent. I will 3d print jigs to hold a steel drill bushing to guide the bit and hold the baffle securely. This will make my end result slightly different from what is recommended on here I think. More on that below, my biggest questions in bold.
General design intent: 9mm subsonic, 8" OAL, 1.375" diameter. Bore drilled to .406" (1)too small? could go up a bit to .422". (2)Should end cap be bigger?
SDTA booster
1" SS blast chamber/spacer
1 - SS blast baffle (3)should I drill an additional 4 holes around the face? If so, any recommendations on size?
5 - AL baffles
Vent hole drilling (bits visualized by blue and purple): both operations will be done with a 3/8” drill bit.(4) Is this the right size for 9mm?
The face will no longer be flat, the drill bit will leave a pointed indentation. (5)Does anyone think this will be a deal breaker? I could fill it in with something high temp maybe…
The halfmoon vent is .375” x .22” (6)does this feel about right or is it a bit too big?
(7)There isn’t any overlap between the two operations. Is this okay?
(8)Is it worth trying to come up with some alignment system? I could drill a 1/16” hole near the edge of each baffle and run a long hardened 1/16” pin through all to maintain alignment.
Pictures below, many thanks for anyone with the time and experience to comment on this!
(note the sharp edges, I plan on softening these with the dremel)
(note that the operations do not overlap, I read once on here that they should, but wasn't sure if this was widely accepted)
(drilling jig models)