300BLK Integral Suppressor

[curtistactical]

I'm thinking of doing a 300 blk also. I'm still deciding if it's worth the time. I already have a .30 cal can.

Not sure what 30cal can you have but most designed for 7.62 can be beat by a good 9mm can with sub sonic 300blk.

[clark4283]

I'm thinking of doing a 300 blk also. I'm still deciding if it's worth the time. I already have a .30 cal can.

Not sure what 30cal can you have but most designed for 7.62 can be beat by a good 9mm can with sub sonic 300blk.

I have a thunderbeast.

Do y'all think cones would be best for a integral or some other baffle type?

[curtistactical]

I have had better luck with K baffles on 300blk sub sonic, super sonic cones would be my choice.

[clark4283]

I have had better luck with K baffles on 300blk sub sonic, super sonic cones would be my choice.

I was thinking cones for ease of building. Plus I will be shooting subs and supers.

I see most folks weld the tube to the barrel to keep it a one stamp gun. The heat from welding doesn't affect the barrel? I'm not a welder so I will have someone help me with this part. Any info on this will be appreciated.

[nbw123]

I built a 300 BO Ti suppressor and welded it to an 8" barrel. I used 3 cones followed by 3 K baffles. Works great with subs and supers. It fits under the handguard.

[curtistactical]

I used 3 cones followed by 3 K baffles. Works great with subs and supers.

This works great across the board, I use 2 cones and 3 K's on my standard production cans.

[clark4283]

K baffles are pretty much self explanatory but what spacing do you suggest i use between cones?

[curtistactical]

K baffles are pretty much self explanatory but what spacing do you suggest i use between cones?

My first 2 cones have 1" spacing.

[clark4283]

K baffles are pretty much self explanatory but what spacing do you suggest i use between cones?

My first 2 cones have 1" spacing.

Thanks for the help. I think y'all have just forced me to send in a form 1.

[LostintheAOs]

Ok, so after looking at my "finalized" design for a while I came up with a possible change and am looking for input on it. I was thinking that for the end of the barrel (the threaded part) I could radius the edge to form a kind of "divergent nozzle". My theory (which if wrong will be quickly squashed by one of you, likely CL or CT) is that the divergent nozzle will cause the gasses to expand faster into the cones and help with sound dampening. Any thoughts? As I said before, shoot it down if it's stupid, I'm pretty thick skinned, lol.

[T-Rex]

Ok, so after looking at my "finalized" design

Post it up for viewing, please.

form a kind of "divergent nozzle". My theory is that the divergent nozzle will cause the gasses to expand faster into the cones and help with sound dampening.

I have little experience with actual implementation of divergent cones, but isn't the purpose of them to create higher velocity gases at a lower pressure?
I would think this is the opposite of what we are trying to do with a suppressor's internals.
Also, with a divergent cone, don't you need to restrict the gases with a smaller diameter? Your suppressor bore is greater than the barrel bore. You'd need to make a chamber after the muzzle to allow the gases to expand so they could be compressed again, no?

I think by having an expansion/blast chamber and allowing the gases to rapidly expand, into what starts as atm pressures, you're decreasing both the pressure and velocity at the same time (with the exception of any unburnt powder still expanding).

There might already be a patent out there that specifically addresses this issue?

[LostintheAOs]

Post it up for viewing, please.

on page 1.

I have little experience with actual implementation of divergent cones, but isn't the purpose of them to create higher velocity gases at a lower pressure?
I would think this is the opposite of what we are trying to do with a suppressor's internals.
Also, with a divergent cone, don't you need to restrict the gases with a smaller diameter? Your suppressor bore is greater than the barrel bore.

You are thinking of a convergent/divergent nozzle, as you would see in an eductor, which uses 2 of them in the housing. The first one decreases pressure while raising velocity, while the second one reverses it. They are tuned to optimum performance by using exact sizes and radii. The second nozzle has an entrance smaller than the exit size (the energy change and momentum maintains the seal), where as the first one has a large entrance and small exit(large change from pressure to velocity).

A slow convergence with a fast divergence gives you a high speed with low pressure, and a fast convergence with a slow divergence gives you lower speed and higher pressure. Being highly tuned with the sizes is what makes them work. Having only one nozzle makes it work differently. Sharp edges generally result in turbulent flow, whereas a divergent nozzle would (in theory) result in smoother flow for the expanding gases

[T-Rex]

Post it up for viewing, please.

on page 1.

This one?

You are thinking of a convergent/divergent nozzle

Yes, yes. Please, forgive me as it's been awhile since high school rocketry.

The divergent nozzle, expanding cone, is really just used to focus the energy/media/gases.
I would think a flat out expansion chamber would yield better results considering the fact that you're allowing the gas to expand wildly, not controlled by the cone, and, being such, they cause disruption unto themselves while having the additional space to envelope and bounce rearward back towards the muzzle before escaping.

Now, if you coupled this with the PH "snorkel" design, where the cone forces the gas to expand directly into the outer chamber, I could see a benefit.

I think the real benefit is by tuning the blast area/chamber to the specific gases* (cartridge, load, bbl length, etc.) rate of expansion so you could catch them in the corner where the first cone/baffle/face meets the tubing wall and cause the most damage to their initial path. Obviously this limits the suppressor's design parameters.

[LostintheAOs]

Just my basic thought process right here.

[Capt. Link.]

Ok, so after looking at my "finalized" design for a while I came up with a possible change and am looking for input on it. I was thinking that for the end of the barrel (the threaded part) I could radius the edge to form a kind of "divergent nozzle". My theory (which if wrong will be quickly squashed by one of you, likely CL or CT) is that the divergent nozzle will cause the gasses to expand faster into the cones and help with sound dampening. Any thoughts? As I said before, shoot it down if it's stupid, I'm pretty thick skinned, lol.

If you are referring to the crown of the barrel don't do it.A muzzle crown affects accuracy more than
any one part of a firearm.I prefer a 11* target or a recessed 11* crown.A suppressed weapon may experience erosion of the muzzle a touch up will restore accuracy.Asking questions is intelligent stumbling forward without asking is stupid.

Use something like this as a blast baffle and it will provide a similar effect.

[LostintheAOs]

If you are referring to the crown of the barrel don't do it. A muzzle crown affects accuracy more than
any one part of a firearm. I prefer a 11* target or a recessed 11* crown. A suppressed weapon may experience erosion of the muzzle a touch up will restore accuracy.

I figured it wouldn't be a big deal considering everything else being done to the barrel (cross drilling, etc.) would result in significant turbulence inside.

Asking questions is intelligent stumbling forward without asking is stupid.

That's why I'm here. It's hard to learn the good ideas if you don't also learn the bad ones.

[whiterussian1974]

wouldn't the main shell of the can (as shown in the first post) have enough volume for what you are saying? the photo of the drilled barrel was just to show how the barrel itself would look.

I am wondering this same thing.
I threw the following design together rather quickly just to show the same idea a bit differently.

Please forgive if this was already covered. I just rapidly scanned the prior posts, so probably missed it.
But I think this use of several small ports in the high Pressure region is better than a large port. (and for non-.22lr definitely better than a double set of coupled-bores.)

Low pressure rds like large holes. High Pres prefer small holes. This takes advantage of several fluid flow principles.
1st: the gas rapidly expands and slows when transiting through a small Fixed-valve opening.
2nd: Since this is your 1st expansion chamber, it has the longest time to fill w gas. So becomes a large sump. Then, the mass must struggle under a low pressure (normalized) force to reenter the tiny holes. Whereas the large hole further down the can both rapid fill AND evacuate the chambers.

I'll have to reread which suggestions prompted you to change from your 1st design. But Cpt and CMV designed their project for 10/22s that would convert Standard .22lr @ 1255fps, down to Subsonic and make best use of the low cartridge pressure to fill each chamber.
(BTW: They did an excellent job w their build. I love how they used assymetrical boring to cross-jet each chamber Entrance! Maybe 1 day I'll try to replicate it, now that I've got a 10/22 Tactical.)

[Capt. Link.]

A design like this is very basic but with some work can be effective using subsonic 300blk loads.
I would extend the suppressor tube to the full length of the barrel if you have not yet filed.Porting,volume and the use of diffusion material will be key to your success.This is close to being a classic 1950-1960's design now where is my AMF book.......

You must have access to a lathe and a good drill press to pull this off.The use of a welder or hard solder will ensure accuracy and would be wise dollars spent.

[whiterussian1974]

I just noticed that the red lateral bores have a small hole facing muzzle.
In CMV's build they were toward cartridge chamber. This allows the gas to plume prior to entering the main expansion chambers. So this is correct placement.

You could enhance the design by adding "Micky Mouse Ears" at top-right and bottom-right of bore positions. this also adds wedges like in many monocore designs. A Little extre volume, too.

[T-Rex]

The smaller, cross-drilled, semi circle at the exit of each chamber is met by a mirrored cut on the opposite side at the entrance to the next chamber. I might be wrong, but I thought the 2 would create a disruption right as the gas enters each chamber. You could add many different types of cuts, in various spots, to cause added disturbance to the flow.

Would ceramic fiber be an acceptable material for the ported, gas expansion chamber?

[whiterussian1974]

The first image illustrates all the Bore holes. The second shows how barrel appears after all boring completed.
The blue box is slightly oversized boreline so bullet doesn't contact metal. The brown lines are baffles seperating the chambers.


ETA: T-Rex beat me to finish typing while I was drawing and uploading pics. So some overlap in our posts.
I agree about cross-jetting, just thought it needed stated directly to eliminate any misunderstandings.

[whiterussian1974]

I'm in the planning stages of a 300BLK integral suppressor. I've come up with a basic design that uses "baffles" drilled directly into the barrel itself (eliminating alignment issues). I saw this done on a 10/22 and am curious if it will work for 300BLK as well. The can itself will be 2" OD welded stainless pipe with a .065" wall thickness. I haven't yet figured out how to do the baffle plates yet (in between the ports). The original design was intended for a SMLE in 45ACP (De Lisle Carbine), hence the can hanging low on the barrel. The first row of ports would be angled back at around 45*, directing the initial surge of gas into the largest portion of the can (I'm thinking those should be bigger than they are in the drawing). Also, the first 3 rows (as drawn) are "T" ports (down as well as across). This is just a rough idea to start with, so feel free to rip it apart or give new ideas. Thanks.

Not sure if anyone has mentioned it. The original concept had a good point of rearward angling the 1st set of ports. This would also minimize bullet shavings and also act according to the "bore evacuator" concept. (Pushing gases away from the ejection port. Most important for Semis, but also helpful using bolt actions. I even blow down the barrel between shots during practice. I'd use a battery-powered compressed air tube for 30secs if I had one. I've seen Benchrest shooters use them during slow-strings to help cool the bore for consistancy. Others just fire 2 shots to warm the barrel before they begin.)

[whiterussian1974]

YOU could use wooden block spacers in the tube as a jig to TIG weld the baffle plates inside the tube.
Just a thought. I did that before on a nonNFA project.

[T-Rex]

Here is an update I did, tonthe first drawing, but never posted it.



The hatched areas are nothing more than cutaway views.

[whiterussian1974]

Vent Micky's Ears backward. Many successful builds have done this in the threads. It's a more effecient use of space. Otherwise. Great Job. You've got a winner!