Please comment on my design

[cdhknives]

I am working up a CAD model before I start work. I have made it this far. The picture has multiple questions. Please apply your combined expertise and let me know if I am on the right or wrong path. This will be hosted on multiple guns from a 4" bbl autoloading pistol to a 18" bbl bolt rifle.

[John A.]

caliber? Super/sub?

[T-Rex]

I'd guess 22?

Muzzle to blast cone length is huge so expect FRP.
Cone spacing is also very large. Typical 22, and small cal, designs have tighter spacing. My most recent 22lr design has 9 baffles in 4.3".

Any particular reason you're using a 2-piece tube design, instead of traditional tube w/ end caps?

[cdhknives]

...thought I had that in the notes...missed it. 22lr only.

All my lurking here has never given me a good feel for spacing on the blast baffle to muzzle. No rules of thumb seem to be 'published'.

I figured an extra cone or 2 would be easy enough...even after I get started. I can cut some of the skirts shorter and use them as spacers to change up the spacing both in front of the blast baffle and between them all, it is just more work and more loose parts to keep track of.

Mostly I'd like to nail down cone geometry, spacing, and qty. There seems to be a wide divergence on philosophy there from what I read on this forum.

[cdhknives]

Any particular reason you're using a 2-piece tube design, instead of traditional tube w/ end caps?

I am probably over engineering it, but I can't get the threads at the blast end out of my head as a weak point. My design reinforces the threads by including the outer ring of the mount/endcap to take the hoop stress off the tube. I also wanted the barrel endcap to be 17-4 for wear resistance and less galling. In theory I could thin the rest of the tube accordingly but doubt I will. I am willing to trade a little weight for durability but don't want to go to an all SS tube.

[T-Rex]

Cram those baffles in there
Seriously, everyone except SOS is using the "more" theory, monocore technology aside.

Keep your muzzle to first baffle spacing minimal. Like, 1/8" zone.

You'll be fine w/ a traditional rear cap.
3/8-1/2" of 20-28 TPI threads and you'll be all set.
17-4 is fine, just trepan or drill-out the inside to reduce some ozs.

[propeine]

Any particular reason you're using a 2-piece tube design, instead of traditional tube w/ end caps?

I am probably over engineering it, but I can't get the threads at the blast end out of my head as a weak point. My design reinforces the threads by including the outer ring of the mount/endcap to take the hoop stress off the tube. I also wanted the barrel endcap to be 17-4 for wear resistance and less galling. In theory I could thin the rest of the tube accordingly but doubt I will. I am willing to trade a little weight for durability but don't want to go to an all SS tube.

A) Its a 22. No need for overbuilding. Cans aren't generally made like that for even 300WM
B) You can do more than just cones and it will perform better on 22lr unless you're intending for supersonic only
C) More baffles! Probably 8ish?
D) Yondering will disagree but I don't like aluminum on cans that need cleaned a lot...ie 22lr
E) 1/4" - 3/8" is probably plenty for 22lr. I think I have 5/16" with K baffles.
F) Your mount and endcap are going to be heavy as hell. May as well thin it out in the threaded area and undercut the end cap
G) ....well i don't know but I would read some more

[cdhknives]

Here is an update with the 'traditional' endcap and more baffles. I plotted it in color so the 'threads' don't show up well.

I am using the YHM barrel thread plan for 1/2-28 TPI muzzle threading to set up my spacing. That calls for about 1/2" from shoulder to muzzle crown, so I left 3/4" from the face of my endcap to the blast baffle. Nominally threaded barrels then give 1/4" gap, more or less depending on the barrel. Short of a muzzle brake mounted can like my YHM QD mount I don't see an easy way to regulate this gap further without truing up all my barrels. That leaves just under 1/2" of threads to mate with the barrel.

Undercuts for the endcap were always planned but I hadn't gotten there yet...they are now shown. The mount cap probably gets pin holes drilled for a pin wrench. The undercut would be really narrow...

[ECCO Machine]

Forget the .062 wall 6061 tube, spend the money for gr. 9 Ti. You can thank me later. Buy .042" wall, thread it 28 pitch 3/8" deep, thin the tube out to .025" in the middle. It'll be lighter and stronger than the .062" wall 6061, and will increase the internal volume. 6" of that tube will run you $10 plus shipping from Tiger metals: https://www.tigertitanium.com/storek/Tube/3Al-2.5V

More baffles. In a 5.7" long can, no reason for fewer than 9 or 10. Machine the spacers into the baffles. It's more material, but aluminum is cheap. And use 7075; it's stronger and machines better. You're using so little that the cost difference is negligible. I would make the cones .025" to .030" thick, except for the blast baffle, which I'd do at .040" to .050".

.22s don't really need a blast chamber, so you really only need enough room that your muzzle won't bottom out on the blast baffle.

Use the 7075 Aluminum for your rear cap to save weight, but make a thin insert out of hardenable carbon steel or stainless steel that actually threads onto the muzzle. Or even thread the base 5/8-24 and Loctite in a commercially available 1/2-28 to 5/8-24 adapter.

If you do this, you'll have a great performing little can that weighs just 3-4 ounces. I make 2.9 ounce monocores with 7075-T651 and .023" wall Ti sleeves, and they'll handle .22 WMR all the live long day.