Distance to first baffle

[bottomdweller]

I'm building a suppressor for a subsonic 50 alaskan. Reflex design by default of the long muzzle brake. 8-60 degree 17-4 stainless m-baffles in a 12 inch long by 2 inch tube. My question to the experts here, what is the best distance from the end of the muzzle brake to the first baffle?

[John A.]

I can't offer any specific advice, though you mentioned that it was going to be a reflex can.

My thoughts on the matter are the closer the first baffle is to the muzzle (or front of the muzzle brake if you're using one) is going to allow more gas through the expansion baffle because it hasn't had time to expand well.

So, moving the blast baffle farther away should let it expand more/better.

From studying many Euro reflex designs, they only use a few baffles near the exit side of the suppressor. The rest of it's essentially empty space.

You may would also benefit from porting the barrel underneath of the reflex part of the can that covers the barrel so you can redirect and catch much of it.

And there are ways of directing the ported gas to make a "swirl" of gas by using different ports drilled at angles that may benefit you too. Though don't get too extreme at the angles. You don't want the cheese grater effect on a bullet.

[bottomdweller]

Thanx for that John. Don't want to port the barrel. It's going to be used at the house but not in the field because of the weight. If I made it out of aluminum it would still be heavy and big. I'm having a hard time uploading a diagram of my idea. How did you do do the drawing you posted on high/low pressure?

[John A.]

I just drew the picture and scanned it into my computer. Then uploaded it on one of the free web hosting sites.

tinypic.com is doing a lot better than photobucket, which is too jinky and glitchy and slow these days.

[bottomdweller]

Come on Capt. Link..... You said you'd help anybody, no response...I really want your input.

[vaeevictiss]

That's a lower pressure round isn't it? If that's the case you probably don't need a ton of space. I went with about 1/3 of the can in my rifle cans so roughly 2.5" give it take a tenth or two.

Being lower pressure and a reflex i'm willing to bet you would be good with 1.5".

But it's just an estimate with no science involved in my assumption.

Will this be a teardown can or sealed?

[bottomdweller]

I'm gonna weld it. But... With a plasma cutter......I'm good.

[Ghost-Delta]

I would give it approx 1". I wouldn't go any more than 1.5" personally. I know of some that have had excellent results without much space before the first baffle, especially considering the diameter of your build.

Hope that is somewhat helpful.
Happy shooting!

[bottomdweller]

So regardless of the distance, should I port the second mounting point, or try and keep that initial gas expansion separate from the blast chamber?

[Capt. Link.]

I'm happy to help but I don't always read the mail send PM next time.I'd plan on 5/8 min 3/4 max spacing between the TWO chambers.I would like to know more about this build,spacing/host?
-CL

[bottomdweller]

So this is the host rifle. It was built for me by SSK industries. It's set up for subsonic use with a 1-8 twist. With 647 gr. pulled 50 bmg ball, shoots 1 inch groups a 100 yrds no B.S! I know the deer is small but I had to shoot something with it. The brake is a 50 beowulf that fits back over the barrel and is then locked down with 4 set screws. The can mount will be welded to the rear of the brake so that it can be taken on and off, leaving the brake attached. The m-baffles are being built by Juliet Delta Customs. They are .80 inch long. The second mounting point is to help everything stay inline similar to what sub-sonic did with his freeze plug build. Should I port it so the two chambers can equalize?

[John A.]

5/8 min 3/4 max spacing between the TWO chambers.
-CL

Do you really think that is adequate spacing for any meaningful expansion?

Serious question.

I've watched a lot of slow motion videos showing muzzle expansion, and it takes it a while to swell out.

pause it at 10 seconds for one example, then pause again at 11 seconds and looks like the expansion needs at least that much room in a 9mm. Larger bore may would need even more, depending.

https://www.youtube.com/watch?v=7y9apnbI6GA

[Capt. Link.]

5/8 min 3/4 max spacing between the TWO chambers.
-CL

Do you really think that is adequate spacing for any meaningful expansion?

Serious question.

I've watched a lot of slow motion videos showing muzzle expansion, and it takes it a while to swell out.

pause it at 10 seconds for one example, then pause again at 11 seconds and looks like the expansion needs at least that much room in a 9mm. Larger bore may would need even more, depending.

https://www.youtube.com/watch?v=7y9apnbI6GA

You can't compare a 9mm to a 50 Alaskan,one is high pressure the other is low.The actual distance to the first baffle would be 5/8 Plus the length of the brake.If you add up the cubic inches of total blast chamber before baffle #1 its huge.A more difficult problem will be getting the suppressor stack to fill with gas effectively.
-CL

[John A.]

I didn't really take into consideration the length of the brake. Especially if the brake is ported. I was just thinking about from the end of the brake to the first baffle face.

As for filling the entire stack with pressure, I believe turbulence would be most beneficial to help direct some of the gas pressure away from the centerline of the bore. The longer it takes the gas to exit to atmosphere, the more effective and likely more quiet that it's going to be. Perhaps stepped cones, scoops, maybe some directional dater holes?

[fishman]

I believe turbulence would be most beneficial to help direct some of the gas pressure away from the centerline of the bore. The longer it takes the gas to exit to atmosphere, the more effective and likely more quiet that it's going to be. Perhaps stepped cones, scoops, maybe some directional dater holes?

What else is new? Lol

[John A.]

There's only so many ways to do it.

I can think of a few more, but I don't know if it would affect the bullet. And with a bullet that big, I don't want to get too crazy. It would probably take the gun out of his hands and throw the whole thing downrange if he were to have a baffle strike.

What would you suggest he try?

[bottomdweller]

5/8 min 3/4 max spacing between the TWO chambers.
-CL

Do you really think that is adequate spacing for any meaningful expansion?

Serious question.

I've watched a lot of slow motion videos showing muzzle expansion, and it takes it a while to swell out.

pause it at 10 seconds for one example, then pause again at 11 seconds and looks like the expansion needs at least that much room in a 9mm. Larger bore may would need even more, depending.

https://www.youtube.com/watch?v=7y9apnbI6GA

You can't compare a 9mm to a 50 Alaskan,one is high pressure the other is low.The actual distance to the first baffle would be 5/8 Plus the length of the brake.If you add up the cubic inches of total blast chamber before baffle #1 its huge.A more difficult problem will be getting the suppressor stack to fill with gas effectively.
-CL

Well I am definitely into making the whole affair shorter if the consensus is that my volume is too much to fill.

[Capt. Link.]

Well I am definitely into making the whole affair shorter if the consensus is that my volume is too much to fill.

I would keep the length and reduce the diameter and baffles used.K baffles would work well or lots of ported cones.
-CL