9x39 project

[John A.]

Got the efile done Friday and mailed the prints off Saturday. They should get the prints today or tomorrow (I haven't checked the tracking).

I think that I have decided that I'm going to use about 3 different kinds of baffles in there. That way I can arrange and rearrange their orientation until I am happy with how it sounds. Of using 3 different baffle types, I should find at least one combination that sounds good LOL

There will be about 10 inches of room inside of the front section of the can that I will be able to fit a lot of baffles in there. I don't plan on making any of them longer than 3/4". Perhaps maybe even the last several even shorter than that.

[x39aesthetics]

Made any progress?

[John A.]

Yes sir, and that's perfect timing. I planned on posting about it this weekend.

I got the approval notification earlier this week and was able to take it out for its' maiden voyage just before dark yesterday. I was more than pleased on how it turned out.

Here's a short video I threw together this morning.

https://www.youtube.com/watch?v=iLOOGAw6hyM

And a quick pic

[x39aesthetics]

So I just noticed your barrel porting. Since they're not synchronized with the 1:7" barrel twist rate, are you running into any accuracy issues having drilled into lands and edges? What'd you do to shroud the ports?

[John A.]

I have observed no accuracy issues whatsoever.

The ports were shaving some of the exterior of the jacket for a while, but that seems to have settled down now and I suspect that it is going to continue to get better and be less with use. When I took it apart the last time, there were only a couple pieces of jacket shavings, compared to quite a bit when I first did the porting.

I do have an internal liner over the barrel about midway between the barrel and the ID of the integral tube portion, but I did that mainly so the portion over the barrel was transformed into 2 large chambers instead of just one large one. The barrel was ported nearer the muzzle, and the internal tube was ported on the opposite side nearer the receiver.

[x39aesthetics]

Interesting, so how did you go about attaching that? Is the suppressor still mounted to the muzzle threading? Is the integral section open to the baffle section at all? How are you sealing the end closest to the receiver?

[John A.]

I'll try to explain how I held the inner tube in place over the barrel and under the suppressor tube.

To be able to explain it though, I need to tell you that I made my own internal muzzle brake that screws onto the muzzle threads. I'm going to call it a diffuser for the rest of the conversation because it serves multiple purposes.

I machined the back of the diffuser to the same ID of the suppressor tube mainly to reinforce the tube and make it stronger since it was so long and the outer tube slides over it and continues back over the barrel.

And In the back of the diffuser, I simply machined a groove the size of the smaller diameter inner tube to fit into, so when I threaded the diffuser onto the barrel threads it tightens against the inner tube and basically just tensions and holds it in place in between the rear cap and the diffuser.

There is also a groove on the front of the rear cap for the smaller internal tube to ride in too of course.

[x39aesthetics]

Neat, so the springs keep the tube under tension even though it's attached all the way at the gas port. Is there anything in between the rear end cap and the barrel or did you just machine it out to .750" for a tight fit?
Working on my design and I'm trying to find a way to have the integral portion be a c-cell tube to fit under a handguard, with the baffle section be a d-cell or larger. Best solution I've come up with is using a lathe to cut a c-cell groove on top of the 5/8-24 to D cell adapter and welding them together. Did you do anything to allow gases to escape the integral section or is pressure just so low that it's not a problem?

[John A.]

I didn't use springs.

I just made the inside tube that goes over the barrel long enough to fit between the back of my diffuser and tension to into the face of the rear cap. It took several passes on the lathe shaving the length of the tube until I was happy with it. But I got there eventually.

I didn't make any place for the gas to exit once it enters there. It kind of just eventually dissipates back through the ports and into the barrel and out of the can eventually.

I think I know what you have in mind to mount your can. Let me send you a PM that may work better for you than what I did.

[x39aesthetics]

So what's keeping everything together then? Perfect balance between the first baffle spacer and the inner tube?

[John A.]

No, it involves my diffuser, but I sent you a PM similar to what I think you have in mind. Sorry it took so long to send the PM. Just got busy there for a while.