Idea, need input

[Anonymous]

Hey Donny u back from Extreme …….. can’t find that Cricket receiver E cover on your web ?

~ Greg

[lankoh]

This sound awesome to me

[caboose212]

quote donnyfl:

I admire you guys, how do you intellectually think and respond when Caboose avatar is bouncing up and down. I just caught myself staring at it for the last 5 mins.

:rofl: :rofl: You’re welcome!!

[donnyfl]

hey Greg, yup back from EBR. The side plates are in production and should be here mid November. Sorry for the delay, I have lots of cool new things coming so they’re waiting to finish everything and send in one shipment.

quote GKU:

Hey Donny u back from Extreme …….. can’t find that Cricket receiver E cover on your web ?

~ Greg

[donnyfl]

Caboose, I’ve tried many different designs over the years and the one that works best are the simple ones. No fancy M,K baffles needed. I am in the process of making a suppressor for big bores and no better place to learn then at EBR with the big bore guys. I talked to Doug Noble and Tom’s American Air Arms team. Doug was shooting a high powered condor and had a huge can on it. In it was a simple air stripper and the rest was empty can. It was crazy quiet. I am not exaggerating when I say it was just the hammer. The hammer wasn’t even that loud to tell you truth. My line of suppressors are all mono-cores that allows for air expansion. The big bore one will not be mono-core. It will have 3 sections inside. This will allow you to bore out the hole for larger calibers if needed. if it was one long Mono-core, it’ll be really tricky to drill out a 10 inch rod. Good luck with yours!

[Anonymous]

The more complex the inners in LDC the more it will mimic a straight pass through blast.

Donny have u try a see though, with a clear Lexan can ?
It will help u see and study the lean dust pattern(s) inside ………. very interesting to see.
Silicone lube the inside to help the lead dust stick some.

The more complex, swurly and hi contrasting the pattern is in the expansion chamber the more effective the Mod seems.

~ Greg

[caboose212]

quote GKU:

The more complex the inners in LDC the more it will mimic a straight pass through blast.
The more complex, swurly and hi contrasting the pattern is in the expansion chamber the more effective the Mod seems.

~ Greg

That is certainly true for powderburners, but might not necessarily be true for airguns… pressures and flow characteristics are similar, but at the same time completely different.

Donny- the only reason why I was thinking a ported barrel, is because inside of the AF frame is what I would call wasted space. I know about drilled barrel bushings and such, to redirect some of the blast back into the frame- the concept isn’t new- but that’s still wasted space to me, because there’s no muffling stuff in there. I was thinking about some WW2 suppressed weapons, with their ported barrels and hearing how effective those suppressors were, at least on video. I may give it a go. I may not. I would definitely have to take a while to make sure there’s as little (or no) shaving of the pellets due to the porting.

[Jens]

Just learned a bit about barrel porting by reading this post, interesting concept. Without having had a deep-dive into the topic though, just from what I read, I’d like to share my thoughts with you.

Barrel porting would help to get rid of the air that is in front of the pellet, as long as the pellet has not yet reached the porting point. Once the pellet has passed this point though, a share of the pressurized air behind the pellet would escape through those ports as well, not propelling the pellet any more, there might be some loss in pellet speed. Actually I think that the pellet would even slow down again once passed the porting due to the friction.

If you have a moderator design allowing the air from the first chamber (muzzle side) to escape in another way than through the same hole as the pellet, by using e.g. a ported back wall and redirecting the air to the lost space around the barrel (as done in various shroud designs or AirForce’s design using the drilled barrel sleeve) and porting the (breech) end of the shroud to let the redirected air escape gently, this part of the air would not contribute to the discharge sound at the moderator’s exit hole any more. You, as the shooter might hear part of it, but the target side wouldn’t.

Again, just my thoughts, might be completely wrong, I’m open to be corrected and learn.

[caboose212]

You could be right PapaS, about how the muzzle blast and air would react with the barrel ports… I have no idea! :biggrinn:

The rest of your post is essentially how everyone already suppresses their AF guns- ported barrel bushing, empty air, then a LDC at the end of the frame, and maybe venting the frame.

I have another idea that Dyotat (via Donny) inspired…

It begins with the barrel protruding enough from the frame, so that the muzzle will ever so slightly extend past the “1 piece barrel bushing/threaded adapter”.

Here’s a few pics- these are from a forum member from another forum:

This large threaded adapter is actually 1 big piece of aluminium, that does a few things:

– Takes the place of both barrel bushings
– Fills the space between where the front barrel bushing would be, and the end of the frame
– Creates an attachment point for the LDC

In the picture, the muzzle doesn’t extend past the threaded section of the adapter- but mine would. Not sure by how much… It is just an idea I’m toying with at the moment.

I’m thinking of using a “Wix 24003 fuel filter” as the actual LDC. I’d get a new end plug and drill the proper hole… I’m thinking a 1″ long blast area right at the muzzle, maybe 1 or 2 baffles, but the rest of the LDC would be an empty expansion chamber. It’s a 2″ OD tube… with 1.75″ ID. It might be enough to tame the beast. The expensive part will be the 1 piece adapter. I’m not sure anyone will want to make that… and I’m sure I won’t want to pay that money! :rofl: I’ll figure out a way to do it though. I think this idea has the most promise.

Thoughts?

[caboose212]

Another idea I just had is to make this adapter 2 pieces- The 1 piece barrel bushing, and the threaded adapter. Make the two have a tight slip fit, and bond them with Loctite retaining compound… or something. I don’t think normal epoxy will be thin enough or strong enough to do this right. All said and done, once bonded, they would look similar to the pictures above. It would just be a bit easier to make, instead of making the thing out of 2″ Aluminium round stock and machining it down and boring it and such… Just a thought.

[Jens]

I understand your idea is more like a classic suppressor, possibly got that wrong in the beginning.
First an expansion chamber then a baffle, then a second chamber or no baffle at all. Both seem to work. In this case you don’t use the space in the frame around the barrel.

Some food for thought:
Don’t know whether you know the Weihrauch suppressor. Basically 2 baffles in between 3 hair curlers wrapped in felt. Makes 3 chambers, lengths around 2/5 – 1/5 – 2/5 of the total length of roundabout 20 cm. I mention it as I have one and in my opinion it’s quiet efficient (pun intended). Could give some ideas, might even keep the 2nd baffle out and have a bigger 2nd chamber (4/5 th of total length).

Another suppressor I have is a one-chamber, but only 12cm total length Huggett, which performs well. Inside theres just a stainless mesh, a thin felt layer against the tube and a lot of space. The newer ones are vented on the muzzle end.

Both work well. I think Rick’s right about reading for some theory, on the other hand most of it is written for firearm suppressors and might not apply to airguns though.

The simplest seem the best, as Donny said and he knows what he talks about… I was baffled (ok, ok, 2nd pun of the post), first by the Weihrauch with it’s hair curlers and then the Huggett which is shorter but even more simple (sorry Donny, don’t have one of yours yet).
If using baffles, thing is to get everything aligned and symmetric, on the other hand, same thing for the alignment of the end-cap.

Anyway Caboose, great project you have, keep the ideas coming and exchange up.

[caboose212]

I probably should have mentioned… These are intended for .30 and .357 airguns… :biggrinn:

[Jens]

You did as far as I remember.
Lots of air to tame…

[caboose212]

Ahh, so I did.

[caboose212]

So I’ve decided that I’m definitely going with a 2″ OD tube for my LDC for the .30 bullpup. Basically it’s a Napa 4003 fuel filter. Again, this is FOR AIRGUN USE ONLY. What are your thoughts on:

A) Using it as is with very minor changes (end cap and such).
B) Run it with a 1″-2″ blast section, one or two baffles and mostly empty.

I’d like the .30 to be a backyard friendly 60+ fpe bullpup. Thoughts?

Here’s a pic of what I’ll be using, and the filter element:

[Author]

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