Muzzle brake discussion

[High-PSI]

Hey Guys,

I am working on a muzzle brake and I wanted to get some good discussion going about these things.

From what I can tell, a rearward discharge muzzle brake reduces recoil and can increase accuracy. I am assuming the heavier the projectile and the more pressure used, the more affective the brake. Is that correct?

I have done some reading on-line and I just wanted to get some feedback from you guys on this. I mean, is it even worth while on an air cannon or are brakes only affective on a firearm (due to the high pressure)?

Matt

[Gun Freak]

On your cannon, I bet there will be a difference. I would try one similar to the M82 muzzle break.

[High-PSI]

Here is my brake so far. It is not installed yet (I have to vent the longer barrel I have at the shop first). But, you get the idea.

I have two hours in it so far.

I actually do not like the look of it as it sits. I think it will have to grow on me. Besides, I still have to disassemble the cannon and powder coat and anodize everything. But, I have other modifications to do first.

Matt

[Gun Freak]

Are the holes in the barrel the same size as the rectangles?

[High-PSI]

Sort of. The round tube the discharge ports are welded to has the profile of the ports cut into it. The barrel will be slotted so there will be two separate long slots running the length of each set of rectangle discharge slots. That way the slug will be supported at 4 points around the perimeter so it cannot wobble in the barrel.

Oh, the reason for 3 sets of ports is purely due to the length of my slugs. I wanted to make sure the slug was still well into the barrel when the brake windows became exposed.

The thing is, I do not want to just add crap to this cannon unless it will actually make a difference. It is not for adding accessories to. This cannon is for performance. Luckily, I have a second barrel (6 inches longer to accomodate the brake) that I am modding for this project. That way I can go back to my original barrel if this brake is ineffective. Heck, I only have $25 and two hours in it so far. No big deal..........

Matt

[saefroch]

The muzzle brake will probably be somewhat functional as it is now, but recoil reduction will probably be minimal (because most of the momentum comes from the slug's velocity). Most likely it will just dampen the muzzle blast downrange, but directing the expansion uprange.

For the record, I think it looks pretty awesome.

[mark.f]

I would like to add to the record as well... that thing looks sweet.

Not sure how effective the muzzle brake will be, as it depends on the mass and velocity of the exhaust gases. A powder burner definitely has you beat on the velocity bit, but in mass I think you may have an advantage, depending on the pressure you use. Since momentum is equal parts mass and velocity (unlike energy with the square of the velocity and half the mass), all I can say is it's a toss up... go for it.

EDIT: Using your launchers chamber volume and pressure (which I ripped from the compressor thread), I calculated real quick that you have about 143 grams of gas available for "reverse thrust". The highest powder load I could look up for a .50 BMG is about 16 grams, so I'd definitely say you had powder burners beat in mass of propellant gases...

[High-PSI]

OK, cool.

My tank is 2 gallons. The tank to barrel ratio is 3 to 1. I run 230 psi on most shots.

The look is growing on me. Oh, also, I need to use my flap-disc to smooth the welds as much as possible. I will, also, use my Dremel to bevel all edges and smooth the inside of the ports as well.

The primary reason for this is, I want to move up to 300 psi and a 1 pound slug. Right now the cannon weighs exactly 40 pounds. Yet, even with that weight, the recoil is pretty strong.

Oh, lastly, I have heard it said that muzzle brakes increase the decibel level. Is that true? Or is it that the sound is, now, directed rearward rather than forward?

Matt

[Ragnarok]

I have heard it said that muzzle brakes increase the decibel level.

It is true from the shooter's perspective, but not the overall noise level. But that is still relevant, because while a cannon with a muzzle brake is no more likely to annoy the neighbours than one without, it is more liable to damage its user's hearing.

At least with regular firearms, it can put dB levels at the shooter over what is safe with hearing protection.
As in practical terms, it's hard to have hearing protection of more than 40 dB (even combining in ear and over ear protection, because sounds can transmit through the bones of the skull), noise levels over about 160 dB cannot be entirely protected against. As you've probably guessed from the general drift of my post, muzzle brakes can put a rifle over that, and hence there are those who prefer to just cope with the recoil - bruises will heal, hearing won't.

I don't know what the risks will be with this, but my normal warning to not forgo hearing protection does go double here.

[High-PSI]

OK. That is good to know.

Honestly, this thing is really not nearly as loud as I thought it would have been. So, odds are, with decent hearing protection, I should be fine.

Of course, we shall see!

Oh, something just came to mind, acoustics are a funny thing. The loudest sound I have ever heard came from a PVC cannon of mine at only 50psi. That was a 1/2 inch valve into a ping-pong ball barrel that was only 4 inches long. That thing was soooo freakin loud, it hurt my ears. I think, in that case, the narrow port, feeding into a much larger barrel that was very short, acted like a speaker and amplified it.

Anyway, I think it is wise to wear hearing protection, regardless.

Matt

[Major Collins]

Well i think the muzzle brake looks alright too just a quick note - i think maybe you only should have holes ported on the top of the barrel instead of left to right so that when the expanding gasses come out the port it pushes downward to reduce recoil but yeah experiment with it i guess

refrence firarms - all glock "c" models eg glock 17c 18c
http://2.bp.blogspot.com/_abaJ0xbRju4/S ... ck-19c.jpg

[hi]

It looks to me like your valve is your weak spot on the gun. I think you should make and all metal piston/diaphragm valve that will handle more pressure.

Other than that I think the muzzle break looks great.

[mark.f]

Well, that is an all metal diaphragm valve. :happy8:

I understand your meaning, though. It might detract from the appearance a bit, though...

[velocity3x]

The primary reason for this is, I want to move up to 300 psi and a 1 pound slug. Right now the cannon weighs exactly 40 pounds. Yet, even with that weight, the recoil is pretty strong.

From the pic, I'm guessing that your barrel is 1 - 1-/12 bore. IMO, I think a 1lb projectile with the medium bore size and only 300psi will be a huge disappointment to you as you don't have nearly enough horsepower to push it. The recoil will no doubt increase but, it will be from the excessive weight of the projectile.....not the gas exiting the muzzle. Muzzle brakes are very effective for the purpose of countering secondary recoil caused by the propellant gas exiting the muzzle ....not primary recoil caused by the projectile.

Great job, Very nice, clean build!!!!!!

[High-PSI]

Actually, it is a 2 inch barrel. It may look smaller because the gun is so freakin huge. But, it is a 2 inch barrel and the bun is nearly 7 feet long at this point.

It fires through multiple layers of 3/4 inch plywood at 150psi. At 230 psi it slams me back pretty hard. I have a youtube link in my 2 inch cannon thread you can watch to see the recoil of the cannon as it sits.

Oh, also, the earlier comment about my valve is correct to a point. Yes, I realize a piton valve is higher flow. However, this valve will tolerate 800 psi per the manufacturer. It is not limited by pressure, but flow. Yet, with a 4 foot barrel, flow is fine. The CV is 53.

As I mentioned, the recoil is intense at 230 psi firing a 183 gram compound round. What I really want to do is move up to 300 psi (my compressor is good for 300+ psi) and a one pound slug. That is the reason for the muzzle brake.

Matt