Dimensions are 7.75" long and 1.375" diameter. Internal volume as pictured is 7.38 in^3. A mount will probably add +1.5" and +0.5 in^3.
This really can't change too much as that is what is on the approved forms and the tube already exists (serialized/anodized).

The threads and blast chamber walls will be 316 stainless and threaded accept Gemtech Multimount modules (LID, direct thread, and 3-Lug). The blast baffle will be thick-ass 316 stainless with ball-milled round "scoops" opposed on each side (kind of like an AAC k-baffle face). Tube, baffles and endcaps all will be 6061-T6 aluminum. All the baffles are actually the same except the last baffle has it's spacer shortened.  Baffles (CNC cut) will be truncated parabolic cones of tapering thickness with mouse holes at the cone tip and the spacers machined integrally into them. Endcap thread is a 28tpi custom diameter where the internal thread minor diameter surface matches the tube ID (1.250"). This makes threading a little simpler and minimizes weakening of the tube. If you had to give it a thread spec, it'd be very close to something like 1-19/64"x28tpi class 3A ().

The projected weight makes me a little weary on it's durability for full auto use... 8.2oz with no mount as pictured.
Is this going to be robust enough for full auto use?

Also, the caliber is technically 9mm, but the bore is a loose because I'm erring on the side of safety being that it is for dedicated full auto use. Ever see a string of baffle strikes at 1000rpm? It's extra bad.

Attached File

I'd not consider .050 Al to be apt for a dedicated FA 9mm suppressor. Go with: thicker Al, Ti baffles, or thin 17-4. TBH, go w/ 17-4 for the blast chamber and baffle. It's cheaper, stronger, and easier to cut than 316. Blast baffle can be much thinner than 316 and still be lightyears more resiliant to heat and erossion,

I'd, also, try to get more baffles in there, especially for FA. A typical 9mm suppressor,  of equal size, will have 8-10 baffles. Go with a spacing around 9/16".

I actually had more baffles in there earlier, but removed some because it looked cramped.
Spacing in the pic is .870 inches and at least there are 8 baffles. Endcap counts, right? LOL.

When you say 17-4... you mean in the annealed/solution state or hardened to something like S17400 H1150?
How thin could baffles #2 and beyond be if 17-4 ... 040"? .030"? I've never done any 17-4

So even though it's the non-blast baffles baffles that are aluminum, you think it would be a problem?
What if I chose 7075-AL for the baffles?

That's not much different than many commercial pistol suppressors rated FA.  Maybe make the second baffle stainless also.  These will take most of the carbon and you can pin tumble those.  Consider reducing baffle spacing  near the front cap to get one more baffle near the end, and no reason for that deep tunnel in the front cap.  I think you have enough thermal mass for full auto 9mm but it depends how many mags you run end to end how hot it gets.  If you are shooting cast lead you probably wouldn't want any aluminum baffles unless you want to clean often via soda blasting.

So going with all 17-4 internals and endcaps, thinning the baffles cross sections to mostly .040" throughout, plus adding 2 more baffles for a total of 9 plus endcap ... the weight jumps up to 13.25oz

Yes, Al can, and has, been used in plenty of FA rated designs. They usually are heavier, due to thicknesses needed, and have larger blast chambers or reflex/over-barrel portions.

Cond A or H1150 are both fine and not difficult to turn.
17-4 can be spread pretty thin so .03 is reasonable, if you can hold tolerances. (Blast baffle use .06 min)
.87 would be ok for the first 2 (being it's full auto), but shrink the rest down near 9/16.
Tubing can be Aluminum as your 17-4 spacers will protect the interior wall.

13.25 isn't bad. The Bowers Vers is 15 and the AAC Tirant 9 is 9.5 so you're right in the middle.

The only reason I can see to make the front cap 17-4 is if you want to pin tumble it.  But if the exterior is painted you won't want to do that, and the front cap won't accumulate much baked on crap if you brush it off periodically. 17-4 threaded into a 6061 tube won't be any stronger than a 6061 front cap.  Plus there is something to be said for a front cap that yields in the event of a strike.  So you might drop a half ounce and have easier machining with an aluminum front cap.  For that matter the last half of the stack could be aluminum.  At that point pressure is low and flame erosion is nil.  But the benefit in all 17-4 baffles is you can rotate them front to back for even wear and long life and just pin tumble the lot at cleaning time.

@User55645

Thanks for the input. I went ahead and did larger spacing in front and behind the blast baffle, then the rest of the spacings are nearly 9/16".
Out of curiosity, how did you arrive at 9/16" for the ideal baffle spacing? Is that common across all calibers? Just pistol calibers? Or just 9mm?
If different, what would ideal spacing for .22LR and .45acp?

I base my spacing off caliber and velocity. Smaller calibers have smaller bore holes and can manage tighter spacing. Use the same distance for 45cal and your bore is so large the gas would slip by.

I start around 3/8-1/2 for 22cal, leaning towards the tighter side the greater the round velocity
Moving towards 5/8-3/4 for 45cal

Baffle design and geometry will also play a role, but this has always proven a good starting point (for me anyways)

You'd be hard pressed to F* up a cone baffle can, spaced at 1/2", for any caliber and/or velocity. It's getting optimal performance out of it where the knowledge and experience comes in.

Why a Gemtech 3 lug?
They're some of the longest and most expensive out there.
I'd look at SiCO pitch and use the Rugged 3 lug from Hansohn Brothers

Adapter options are nearly limitless for the gemtech "B" thread pattern. Lots of mount options from companies other than gemtech that fit this thread pattern.